This page answers the FAQ, "What can I try to keep my machine from freezing or crashing so much in order by level of desperation?" You might like to try simple things first, like the suggestions in our Cribsheet, the Chiron (download) DocMaker presentation or the Troubleshooting 101 (download) desk accessory and come back here if they weren't enough. Those issues that are more model or application specific are left to other pages in the links section such as the Complete Conflict Compendium. Also see the fine explanations in Yale's Macintosh Guide. These sources are especially valuable if you are a newcomer to the Mac. They can help with the most common software and hardware problems. More to the point of this page is the book Sad Macs, Bombs and Other Disasters by Ted Landau. A new third Edition has just been published by PeachPit Press. Ted is the host of MacFixIt and author of the troubleshooting chapter in MacBible.
CAUTION: If you don't backup your data and run your favorite disk doctor software very regularly, your worst nightmare may be awaiting you. Equally important is scanning your hard drive regularly. If your disk doctor utility finds an error and says it was fixed, it pays to run it again to see if it really did, in fact, fix the problem. If it didn't, consider restarting from an emergency floppy and running it again. The author's favorites are Public Utilities by Symantec for System 6 or Norton Utilities Disk Doctor 3.x by Symantec for System 7. Apple has released two programs called MacCheck and Apple Personal Diagnostics, neither of which is widely used.
One kind of preparation that will pay dividends
eventually is to prepare a set of current, bootable emergency disks to
keep on hand for troubleshooting. Minimally, have one with your favorite
disk doctor, one with Apple's Disk First Aid, one with your hard
drive formatting software and finally, one with a virus checker. If you
use backup/restore software, you may want a copy on a bootable floppy.
If you do a lot of troubleshooting, an additional disk with a hardware
diagnostic tool, like Peace of Mind, Snooper or TechTool
Pro can also be helpful. Many other specialized utilities will be mentioned
in this document along the way.
Another kind of preparation is defensive driving, prevention
through good work habits. Save your PRAM settings with a free utility like
Techtool during a period when your machine is stable. In General,
save your work frequently. Try out one new piece of software at a time,
particularly control panels and extensions. Keep a current copy of your
System, Finder and critical preferences handy. If you have removable media,
make sure you have at least one bootable volume containing your current
system software. Try to keep ten percent of the space on your system disk
disk available at all times. If your only hard drive formatting software
is what came with it several years back, make inquiries for getting something
more current.
If you have valuable data on a floppy and inserting it produces
a message saying that it is unreadable, do not initialize it, lock it.
Try to insert it in another drive or even in another Macintosh. If none
are available, try it again after you have successfully inserted a second
expendable floppy. If the floppy is substantially warmer or cooler than
when it was written, it may be harder to read. You may have to try inserting
it several times. Store your floppies in a low dust environment, preferably
a container with a lid.
If you are well prepared, your down time will be minimized.
When a program crashes or freezes, unpredictable things can happen. PRAMs,
boot blocks, and disk directories can become corrupted, so it is important
to find and eliminate the cause in a timely way.
Simple
Application Freezes (no bomb) If your keyboard or mouse goes dead, determine first if it really is a machine freeze or if only the mouse or keyboard is frozen. First, be sure all affected cables are plugged in securely. If you use an alternate pointing device, like a trackball, it may freeze while the mouse is still functional! Substituting a different device that you are confident is working properly may solve the problem.
NOTE! It is not advisable to remove or insert any connectors associated with your Mac unless you first shut down completely! It is possible to blow an internal fuse if you do.
Another trick to outsmart mouse frost is to be able to Save in an application using a keyboard Command-S, very useful if just the mouse dies. In Netscape, for instance, I have additionally installed Command-S on the Save-As menu using ResEdit, for those many occasions when the Save command is dimmed. Only try this if you are comfortable with ResEdit. Other keyboard commands that may help depending on your situation are command-period to cancel a dialog box, command-W to close a window, or command-Q to quit.
If the keyboard is also frozen, your options are more limited. Those using System 7, can hold down the command and option keys while pressing the Escape key to forcibly quit an application. Command-option-escape doesn't always work. If it never works and you want it to, use your extension manager to see if you might have installed an extension called NoForceQuit and disable it. If it still never works, try another keyboard, the Escape key may be dead.
In any case restart your computer as soon as you are done saving any important work, if you are able to do so. The restart can be done via the power key on the keyboard, the programmer's reboot switch (triangle icon) or the main power switch. Each of these is actually very slightly different to the computer. If your crash of your machine is so complete as to be unaffected by pushing the power switch, you can try to hold it in for several seconds or simply unplug it. Powerbook users may have to remove the battery and unplug the power supply on occasion if they are unable to shutdown using either Command-Control-PowerKey or Command-Option-Control-PowerKey.
You may notice a folder called Rescued Items in the trash. It is usually empty or contains useless material.
When a freeze happens while the machine is idle, be suspicious of an extension conflict. See the Extensions Conflicts/Bugs section below.
If the freeze only happens only while printing a document, there may be insufficient memory to run the Print Monitor. System 7 users can try turning on Virtual Memory temporarily to see if the problem goes away. If this doesn't work, try a different printer driver if you have one or you can try increasing your Adobe Type Manager cache setting if the document being printed uses lots of fonts. Test the printing with background printing OFF. Verify that your LaserWriter driver is at version 8.2.2 or greater under System 7. (Be aware that version 8.4 requires the often buggy CFM-68K unless you have a Power Mac). The LaserWriter driver 7.1.2 works well under System 6. Other other newer versions may work, as well.
If your machine freezes or crashes each time you boot it and you have an unprinted document pending, an attempt to print may be the cause. To remedy this, restart the extensions off and double click the desktop printer icon with the X through it. You will see a list of pending documents which you can select and drag into the trash. You can also just drag the icon itself into the trash.
Sometimes a freeze will happen exclusively with a certain CD or floppy. For CDs this may be caused by some kind or dirt or gummy build-up that can be removed with careful cleaning. For a floppy, it may be time to run a recovery program to salvage what data can be saved, before you attempt to discard it. If the recovery fails, you can try copying the whole disk to a blank disk with a utility like Norton's Floppier or try opening any important files directly from the File menu using the program that created them.
A new extension called PowerPC Interrupt Extension was released in the last quarter of 1996 by Apple. It is specifically designed to reduce long waits and freezes users experience on the PowerPC. It requires System 7.5.5 to function. The extension is so new that its interactions with other software is not known at this time. Powerbook users and users of 680x0 machines do not need this extension.
Many of the following ideas do not work consistently, they are for the truly desperate.
If you have a programmer's switch installed, you may also
try entering debug commands for System 6 or 7 .The interrupt switch (circle
icon) allows access to the debugger. Type the following cryptic commands.
Method 1:
G FINDER then press the RETURN key
Obviously, the easiest of all to remember!
Method 2:
SM 0 A9F4 then press the RETURN key
G 0 (zero) then press the RETURN key
This is the so-called exit to shell (the Finder)
Method 3:
SM FA700 A9F4 then press the RETURN key
PC FA700 then press the RETURN key
G 0 (zero) then press the RETURN key
If you accidentally press the interrupt switch, you can resume your work by typing G then RETURN.
Defrosting Software
You won't have to type in any of these silly codes under System 7 if you just install the shareware Interrupt Button extension. If the software works correctly, you just press the programmer interrupt button to reach the Finder.
Netscape Defrost is a handy little System 7 tool to help you recover from some freezes using the Netscape Navigator and possibly other internet programs.
For software that uses the modem, there are the Modem Re-setter and PortCloser applications that might cut down on freezes and crashes when downloading or connecting to on-line services.
If your cursor freezes often, but your keyboard stays alive, you may want to explore shareware like RecognizeMouse, Escapade, or YesNoCancel to help you get by. The RecognizeMouse application tells the Mac to try harder to use your pointer. The other two control panels let you make choices in dialog boxes from the keyboard. Most of us are so mouse-bound that we are not aware that a Macintosh can be operated without a mouse using Easy Access or the freeware KeyMenu control panel. TSM Fix may help the reliability of your mouse by keeping you from experiencing "missing clicks".
If the freezes only occur when using a certain program,
there are more ideas to try in the When you get to
the Desktop) section. For freezes during the restart process, see
the next sections.
Crashes
When does it happen?
1) Before the extensions load (more than likely a Hardware Issue)
2) During extension loading (probably one of many possible Extension Conflicts/Bugs)
3) After extensions load when the finder starts (check Finder/Desktop Integrity)
4) After the desktop appears (see: When you get to the Desktop)
IMPORTANT! Try to recall whether the problem first became apparent with the installation or enabling of new software or hardware. If so, start there. For example, if you had virus detection software turned ON during a recent install, it could have seriously affected your machine and caused your current problem.
Keep a log of your freezes and crashes and record exactly
what you were doing and what exact sequence led up to the problem. Then
record what you tried and if it worked. Patterns can emerge that will help
both you and any technical support people you may deal with later.
Hardware
Issues 
If you use any SCSI peripherals, you may want to unplug the SCSI cable after powering down and then try to restart. The SCSI cable is a heavy wire at least as thick as the power wire that plugs into a 25 pin connector on the rear of your Mac marked by a disk drive icon. If you have recently added a new SCSI device, you should be aware that each peripheral added to the SCSI bus must have a unique ID address number that is usually set by a switch on the back of each the peripheral device itself. The number ranges from zero to six. Zero is normally used as the ID for the internal drive. Make sure there are no duplicate IDs and also that there is a terminator plug installed on the last item in the chain unless internally terminated. A good rule of thumb is to have the highest ID numbers assigned to the fastest peripherals. If you have them or can borrow or buy some, try fresh, short, high quality (thick, gold-plated connectors) cables. Sometimes getting a chain of SCSI devices to work is a black art of trial and error. Be sure you never have two devices in a chain that are both internally terminated. Sometimes changing the device order or temporarily removing items in the chain can help. The total length of the combined SCSI cables should not be over twenty feet. A control panel like SCSI Probe or even better HDT Prober is very helplful.
If you can successfully restart from a floppy, you can first try Disk First Aid on Apple's locked bootable utility disk. If the program terminates with an error message, try running it a second time, just in case. If this is not sufficient you can then try your favorite disk doctor, also from a locked bootable floppy.
CAUTION: If you have a 5200, 6200, 7200 or 7500 Power Mac of early manufacture, it is possible for Norton Disk Doctor to accidentally erase your entire hard drive. To fix this problem, Symantec has released a special free utility called Disk Spot Check. This stark example points up the danger of running the first model or release of any new hardware or software product.
Another procedure is to update the disk drivers in your boot blocks on the system disk drive. Perhaps the simplest and fastest way to try this is to simply drag the System file out of the System Folder, close the folder and then drag the file onto the Sytem File icon and drop it back into the folder. Otherwise you can use Apple HD SC Setup if you own an Apple drive. If you use Silver Lining from LaCie, it will tell you if your disk drivers need updating. Both SCSI Director Pro (now discontinued) from Transoft and HDT Toolkit from FWB Software are serialized, so you may end up crippled in your hour of need. FWB's toolkit is frequently unable to update the drivers in any case. Be sure your copy of any such programs is current and ready to run. It is best to prepare a working copy of your favorite hard disk formatting utility on a bootable floppy in advance, just in case. Once you choose formatting software, stick with one program if you use it on removable media.
NOTE: A floppy disk with bad boot blocks can crash a machine instantly, just by inserting it into the drive. Another problem for System 7 users is 400K floppies. Move all important data off of 400K floppies before you get involved with System 7. "Working with 400K floppies under System 7 is a real can of worms. Don't even try it if you can avoid it. It may simply hang the System, so you have to restart. On the other hand, it may cause the data on the floppy to become totally unreadable under System 6.or System 7. Lock the diskette! You cannot rename a 400K floppy disk, create a new file folder or even see folders!" -- via McOrphan
Be aware that command-option-shift-delete will keep the internal hard drive from mounting during a restart while test-booting from an external hard drive or removable media. If your machine has a CD-ROM drive and you have any bootable CDs, you may want to try holding down the "C" key at the beginning of the restart process to test whether you can boot from a CD. If you set the Startup Disk control panel to boot from another device, remember to set it back to your internal drive once it is running again. If you don't, your boot time may slow down.
At some point in your examination of the machine, with the power OFF, try unplugging all cables. Examine all connectors for bent, corroded or receding pins.
First, reattach only the keyboard, mouse and Monitor, then reboot. Examine the Apple Desktop Bus (ADB) with the ADB Prober utility if the keyboard or mouse are behaving erratically or not functioning at all. It will show you a list of all currently recognized mice, keyboards, et. al. on the ADB bus. A defective mouse or keyboard can cause a machine to crash, so if you can temporarily test your machine with a different set known to be working, it may help to isolate the problem. Be sure to try fresh cables in the process. If the machine does not see an ADB device on a regular basis, you can try RecognizeMouse.
An overheated floppy drive can cause a crash, showing Errors 10 or 15. If this happens you might notice whether your fan is running and whether the weather is exceptionally hot. If the floppy is external, you can try pointing a fan at it.
If you suspect another hardware problem, try running Snooper or the newer TechTool Pro from Micromat at (800) 829-6227. Use them on a bootable floppy, if your hard drive won't boot. If your floppy or hard disk has given read or write errors, be sure to exercise it with a disk utility. Dust in floppy drives is a notorious cause of problems, but is not likely to crash a system unless you have actually booted from a floppy. If the boot block of a floppy is corrupted, inserting the floppy into the drive can crash your machine.
Older Syquest drives are incompatible with SCSI Manager 4.3.x, yet this software is required for the 630 Macs. Good luck if you got caught in this and other 630 squeezes. System 6 anyone? Syquest support can be reached at (713) 307-1850.
The Ethernet Mace controller circuitry that is built into some Macs requires Network Software Installer 1.5 or newer to avoid crashes.
Does your computer monitor display sudden or intermittent changes in color hue? Does your computer exhibit frequent system freezes, where the cursor does not move and the menu bar clock does not advance? If so, you may have a Mac Lemon for which a free replacement or service may be available. While new Macintosh hardware is guaranteed for a year, under some conditions the period is even longer under Apple's Repair Extension Program (800) SOS-APPL.If you have a Macintosh 5xxx or 6xxx Apple has created the Macintosh 5xxx/6xxx Tester just for you. Maybe you will qualify for free help.
The
end of this section is for the hardware savvy only. 
Apple considers most internal personal hardware troubleshooting to be inadvisable. Do so only at your own risk! Be sure to discharge any body static by touching a safe metal ground point after opening a Mac.
SIMM contacts may be cleaned with a pencil eraser and reseated. The tiny plastic clip ears (especially on older SIMM sockets) are very, very fragile. If you hesitate at this point, ignore this suggestion. A safer approach is to test the memory continuously with a ram diagnostic program like Snooper or RAMometer (sys 7) for several hours. If you feel comfortable removing SIMMs, you can more directly verify third-party memory is not faulty by selectively removing/swapping banks of memory. If a sad Mac code shows up on the screen just below the icon, use it to locate a bad module as discussed below.
On Macs with either 72 pin SIMMs or 168 pin DIMMs, you can remove memory modules one at a time rather than in banks. For a Mac with a cache SIMM or board, you can try firmly reseating, removing or replacing it as needed. This can simplify your troubleshooting. If you have third party memory on a PowerMac, ask your vendor if you might have installed an incompatible kind of composite RAM by mistake. Power Macs are particularly susceptible to error 11 and sometimes it is caused by defective or incompatible memory. If you need more information about which memory and options are found on your model, ask the GURU.
If you have a PowerMac with a L2 RAM cache card, you can try removing it to see if the error 11 rate goes down or simply test it with diagnostic software like TechTool Pro.
Nightmare on PowerBook Street from New Technology is a freeware application that was written to detect incorrect memory modules in PowerBook 165c and 180c computers.. Several companies sold memory which added Wait-States to the operation of the PowerBooks. "Nightmare on PowerBook Street" allowed Users to easily test their notebooks and determine if they had been sold incorrect memory.
When starting your machine, if you don't even hear the fan motor or the power cuts out unexpectedly, you might want to check your battery(s). The early Mac II series have batteries that are soldered in, but more current models use a battery holder. A leaky dead lithium battery can seriously damage a mother board with acid, so it should be replaced promptly. If a cell marked 3 V or 3.6 V tests below 3.3 V, it is probably gone or well on the way (Apple says 3.0 to the public and 3.2 to its service people). Testing the battery while it is still in the machine is recommended. The tiny nibs on the battery cover break off very easily. A new cover can be ordered with a replacement battery from Prefix Technologies at (800) 264-2530. A machine with a dead battery may not boot at all unless you put in a new battery or jump start it (techies only). Information from Apple or the Macintosh Motherboard Battery Page may be of help.
If you have any optional items plugged into your motherboard sockets, try reseating, removing or replacing them as availability allows.
When
Macs Go Sad
If all attempts yield only the failure tone and a "Sad Mac", check the screen code for a clue about what has gone awry. According to the Macintosh Guide, the 10 most common sad Mac causes are:
Corrupted Boot Blocks (Use your favorite hard disk utility to install new drivers)
Corrupted System File (Reinstall the file)
Corrupted Finder File (Reinstall the file)
Problematic SCSI Chain (Double check your cabling and termination, check it internally, if needed.)
Faulty or incorrectly installed memory chips (Reseat, rotate, or replace the modules)
Faulty or incorrectly installed expansion cards (Reseat or replace the board)
Physically damaged hard drive (Swap it out if you choose or use command-option-shift-delete)
Physically damaged motherboard (check for resistor-like fuses with markings such as F1 or F2)
Physically damaged power supply (sometimes there is a fuse hidden inside)
For a Macintosh that boots and displays a "Sad
Mac" immediately, the problem is probably caused by either
faulty hardware, corrupted boot blocks or corrupted system files. The hardware
problem may be bad memory. On earlier Macs, a screen code helped determine
which memory SIMM caused the crash or whether it was something else. On
Macs with 72 pin SIMMs or 168 pin DIMMs, you can remove memory modules
one at a time rather than in banks, so no module code is needed. The crash
sound or 'failure tone' varies dramatically by model. You may hear a simple
chime, a dirge, bongos or an auto crash as detailed by Dave's
"The Mac Line." and Marvin's
Sanctum. Ironically enough, playing these .aiff sounds may crash
your computer! If this happens to you, be sure that you have the current
version of your browser and are using only sound plug-ins that were bundled
with it. If the file still crashes your machine, your browser vendor needs
to get some e-mail detailing the problem.
Early Mac
LC/Quadra
QuadraAV
PowerMac
Otherwise, find a Mac technician. If you like to fix things and have an older machine, get an old copy of The Dead Mac Scrolls by Larry Pina if you can find one. For newer machines, you can use Upgrading and Repairing your Mac by Lisa Lee. On-line you can read the hardware FAQs and browse the Phoenix Mac Repair application. Authorized Macintosh dealers do not normally make board level repairs. They swap boards. This practice can be very expensive since there are so few boards.
If there is critical data on a crashed hard drive, be sure you tell the technician. Or, even if there is another cause for the machine problem, inform the tech if valuable information is contained on the drive. Then, if the only option is to reformat the drive, you will be notified in advance. If you are willing to pay a premium price for a data recovery service to try to retrieve it, tell the technician that, too. A data recovery service may advise you NOT to run disk doctor software, because it will lessen their chance of recovering the data with the custom software that they use. Total Recall sells a Data Recovery Toolkit, but there is no way to know if it will work for you because the demo is disabled.
If you are an educational user or you have a new machine
that is under 90-day warranty, Apple can be reached for their free advice
at (800) SOS-APPL. Their Customer
Support Program options are listed in a press release explaining
the termination of their free telephone support.
Extension
Conflicts/Bugs 
Extensions and control panels are files that appear as icons at the bottom of your screen when you startup your Macintosh. The more you have installed, the bigger the chance that one will not get along with another and you will start to have freezes, crashes or other unpredictable behavior either during the startup process or later when you are running programs. These files are found in special folders that live inside the System Folder. Which of these files are in use is normally controlled by extension manager software.
Turn off all extensions using either an extension manager or by holding down the shift key (System 7 or 8) during the boot process. If this solves the problem, then you need to zero in on recently installed or enabled extensions. One method is by using a systematic 'divide and conquer' troubleshooting technique with an extension manager. Extensions load after the system, any enablers, or fonts in an order determined by your extension manager, usually alphabetic within category. Control Panels Load after the Extensions. Apple's Extension Manager has a convenient grouping called "System 7.5 Only" that helps the beginning user distinguish essential Apple extensions from third party software, no small task these days (see the InformInit or ExtensionOverload for an explanation of what is what). The step by step visual appearance of the icons as they load may give a clue to which one of them failed to load or function correctly. The last icon to show up at the time of crashing may give another clue as to which extension caused the crash. If your icons are not labeled with the name of the extension as they march across the screen, you can try using the shareware Extension List control panel.
Another twist is that on rare occasions the order in which two extensions load may be critical. For example, under System 6 the TrueType extension has to load before the Suitcase extension. A way to force this to happen is to rename it to sTrueType (since loading is alphabetic) or to use an extension manager that lets you control the loading order. Bear in mind that the most difficult problems to solve are those where two different problems occur simultaneously masking each other with a similar symptom.
If you know that no new extensions have been installed recently and that your current configuration has been stable, it is possible that a preference file from one of your extensions has become corrupt. This is easy to check for System 7 users because you can simply temporarily drag the preferences folder onto the desktop and try to restart again with your normal extensions on. If your problems disappears, you can look inside the newly created Preferences folder inside the System Folder and decide which of the preference files there would normally contain critical infomation and which are of no consequence. A careful sorting process will probably get you running again. Running a shareware program like Yank before you start this whole process can help weed out totally useless preference files for applications no longer in use. Note that applications like QuicKeys and Netscape keep important files in the preferences folder that may be irreplacable if deleted. At worst you may find that you have to get one or two replacements from a backup volume or recreate it them by reentering the needed data. If you directly delete a preference file for an extension, it is best to do it with extensions off.
One specific file that can become corrupt and is expendible is the MacTCP DNR file created automatically by Apple's MacTCP control panel. It does not live in the preferences folder, but lays loose in the System Folder. It does not contain manually entered settings. A special script is available called DNR Deleter that deletes the file each time a machine boots or is shutdown if this file gets to be a big problem.
For System 7 users Conflict Catcher from Casady and Greene at (888) 227-2394 will help spot some incompatibilities automatically, and other suspicions to check can be deduced from the list of traps in its report. Since Conflict Catcher loads before any other extensions, you have the benefit of its help early in the boot process. Conflict Catcher has many fine features that outshine Apple's freebie. It sometimes detects and disables problematic extensions.
If you have installed software recently and an Installer Cleanup extension persists after several boots, you may want to disable it or erase it manually after booting.
If turning off your extensions eliminated your problems and you want ideas of individual items you can turn off that commonly cause problems, you can try items from the list below first.
Make sure Easy Access is disabled (throw it away if you don't use it)
Turn AppleShare and virtual memory off if you happen to have them on.
For System 7 users--double check for these old or buggy extensions. You can ignore the first three if you do a clean install of current system software.
System 6 users with large hard disks can verify that the extension called Desktop Manager is enabled if you use it on your system. Most people don't. If you have more than about 1,000 files on a System 6 drive, your machine can tend to freeze without it.
Errors 1, 2 and 3 are commonly seen from corrupt or buggy extensions. Such errors may not show up until you actually launch an application and may show as error 11 if you run a PowerMac.
Be especially suspicious about ever allowing two extensions to run on your system simultaneously that do very similar things, like DOS Mounter and PC Access, or Suitcase and Font Juggler. They may both patch the same area of code in the System in a way that is incompatible. WYSIWYG menu utilities and screen savers are particularly egregious in this area.
If certain extensions refuse to load that have worked perfectly in the past and you are on a network, the problem may be a form of copy protection in those extensions that requires a unique serial number for each copy of the software on the network. You can remove the LocalTalk cable before you boot the machine to test for this and reconnect it later. Extensions from Now Software are notorious for this kind of behavior. For applications, it usually sufficient to just turn off AppleShare.
If you don't see any extensions load before your machine gives up and you have ruled out hardware problems, remember that fonts load before extensions. If you can boot from a floppy and remove any non-Apple fonts from the Fonts folder, this may save the day. On very early Macs, it is essential to have Chicago and Geneva available, on newer Macs critical fonts are in ROM.
System 6 users will not have a Fonts folder, the fonts will be loose in the System Folder. A way to avoid this issue is to use a font management tool like Suitcase. If you insist on running lots of fonts and do not have a commercial font manager, you can try to track down name and ID conflicts with shareware like GSF-Rasputin or Font Box.
You can crash with an error 11 if there is not enough system heap space allocated at startup. Conflict Catcher allows you to increase the size of the heap under System 7. If you have a Power Mac and use any Microsoft Extensions, you can try reading Microsoft's Error 11 memo and possibly installing their special Error 11 patch once you get to the desktop, if it applies to you.
Try running Help! from Teknosys at (800) 873-3494 if you own that product. It will make suggestions about incompatibilities that it finds.
Older applications may not behave with file sharing, virtual memory, 32-bit addressing or Modern Memory Manager on and may require compatibility mode to be on if you have a 68040 based Mac like a Centris or Quadra.
Finder/Desktop
Integrity The Finder loads in the period after extensions and control panels have marched across the bottom of your screen, but before menus and desktop icons appear.
If you freeze with a blank menu bar at startup, you may be able to get to the desktop if you just hold down the option key during this period the next time you restart the machine. If this works, be sure to rebuild the desktop by whatever method you choose from those described below. Also note that if the Finder Preferences file under System 7 becomes corrupt, you may not be able to get to the desktop unless you delete it. This is also a good tonic if you experience frequent freezes or strange error messages in the Finder.
The Finder may need to have more memory allocated to it, especially when freezes or crashes consistently happen on the desktop. Under System 6 you can do this directly with Get Info. Under System 7 you may use the utility Finder Size Updater or the extension Finder Heap Fix. The later is the more versatile and available of the two.
You can hold down the command and option keys during the boot period that follows extension loading to rebuild your desktop. This method may be more effective if you restart with extensions off. Better yet you can use a program that erases the desktop file(s) like the shareware programs TechTool or File Buddy for System 7. If you use System 6, you might like to try the shareware extension DesktopReset or Reset DTDBs . A desktop rebuild will discard any comments seen in your Get Info boxes unless you use a method known to preserve them, like TechTool or having System 7.5.3 or above installed. All comments are lost regardless under System 6 or if you rebuild under System 7 when previously running System 8. It can be very disappointing to find that the nice URL pathnames that Netscape has put in the comment box when you save a file have disappeared. The Generic Icon Page contains more detailed information about the desktop file.
If you get a Finder Error 11 and have a Desktop Printer Icon present on the desktop (under System 7), you may want to drag it into the trash. It can become corrupt over time.
If you have eliminated the suggestions listed above in tracking down Finder errors, there is one more thing to consider before replacing the System and Finder. Sometimes the operation of the Finder is modified or superceded by other software that mask themselves as Finder errors. Speed Doubler and CyberFinder come to mind. If you double-click on a corrupt bookmark file with CyberFinder enabled, the System can crash with a Finder error through no fault of the Finder.
If all your files appear normally on the desktop, but are invisible when you want to open them in a program, you might want to try the freeware program Disk Rejuvenator from Aladdin Systems. It repairs a kind of Finder related corruption for both System 6 and System 7 hard drives.
If you can boot from a floppy, but not the hard drive
and have already checked the drive directory structure with a hard disk
utility, you can try to install a fresh System and Finder after removing
the old ones or stashing them each in a separate folder. For System 7,
Apple provides instructions for a Clean
System Install. A clean install is invoked with command-shift-K
at the main window of the Apple installer after you have renamed your System
Folder and hidden your System file in a memorable place, like the Preferences
Folder.
The most important thing to do when you get to the desktop is to run your favorite disk doctor program. Both directories and files can become unexplainedly corrupt and will need occasional repair or replacement from your backups. If the program says it fixed something, run it again and see if it really did. If it didn't, consider booting from an emergency floppy and running it again. If the hard drive contains your only copy of critical data, back that data up to external media as your first priority.
Run the most recent version of a virus program like the shareware program Disinfectant or SAM Virus Clinic from Symantec from a locked floppy if you are exposed to files from the outside world and don't screen them. The Virex program from Datawatch even checks files as you download them.
If file sharing has been in use, use File Buddy to delete the invisible file called AppleShare PDS. A corrupted PDS file may also cause your machine to have a slow restart period.
If the problem is application specific, reinstall suspect program after verifying that you have a large enough memory allocated (the preferred size in the Get Info Box). The ultra slow virtual memory may help you get by for testing purposes, if you don't have this much available memory shown in your About This Macintosh box at the top of the Apple menu. Be sure to try allocating more memory if you have an application that will consistently quit unexpectedly with a message to that effect. If you are running System 7.5.5, note that each application will take 23K of memory more than before. It doesn't hurt to allocate an extra fifty percent more memory that the preferred size as a performance experiment. Amazing results can be had with such a simple trick. Turning virtual memory on can also give a performance boost for the PowerMac if you don't already have RamDoubler installed. There is a very patient and detailed memory allocation explanation in the MacBible (Download) troubleshooting section "What Are All Those Error Codes Anyway?" If you tend to use lots of PostScript fonts in a single document as you would in a specimen book, it may be necessary to increase the font cache in the Adobe Type Manager control panel.
Third party filters and plug-ins can be a subtle source of crashes. If you are troubleshooting an application that crashes and has add-ons, try removing them and replacing them in small groups as if you were looking for an extension conflict. When you upgrade to a new version of a product, you may need to upgrade any third party software as well. For Example, an older extension like RealAudio running with Netscape 2.0 may conflict with the bundled LiveAudio that is now included with Netscape 3.0
Older applications may not behave with file sharing, virtual memory, 32-bit addressing or Modern Memory Manager on and may require compatibility mode to be on if you have a 68040 based Mac like a Centris or Quadra. If your Macintosh is in 32-bit mode and an old application you still want to run crashes, use the Memory control panel to turn off 32-bit operation and see if this helps. If you must do this, you are limiting the amount of physical RAM you can use to 8 megabytes.
Deleting the associated preferences file may be sufficient to fix an application. Such files are normally found in the Preferences folder which can be found in the System Folder. If you notice a pattern of crashes with a particular set of applications, run the shareware Crash Less Often Reporter to see if any of them fail to purge the WDEF resource. If so, you might try using the shareware WDEF Leopard extension for a while.
If your memory problems on the desktop come from Desk Accessories instead of application programs, then you are not able to increase the memory allocation with Get Info. In this situation you can convert the DA to an application with DA Piggyback first, then alter its memory needs.
View your other the contents of your Preferences Folder by date and consider which recently changed files, if any, might be contributing to your problem. Certain applications, like Quark, tend to need this kind of attention more often than others. If this gets to be a nuisance, keep a floppy with a backup copy of the worst offenders. Be sure to put key files from your Netscape preferences folder on the floppy too, like your preferences, bookmarks and global history.
Remember that many extension conflicts do not actually show up until you begin to launch applications. They commonly manifest as errors 1,2 and 3 on 680x0 based Macs and error 11 on PowerMacs. If you boot with just a set of minimal Apple extensions on and experience no problems at all, then be very suspicious of an underlying extension conflict or bug. There are several applications with printable error charts - MacOS-Error-Guide, System Errors 7.0.1, Mac-Error-Codes (in German). The most explanatory lists, however, are on internet web pages. I think the nicest is Macintosh-System Error Codes Explained. In real life charts are a poor way to pin down problems because they can seldom give useful advice on just what to do to eliminate the error. Most of the time error codes are really there to help programmers fix bugs, not to help users. Be sure to mention the exact text of an error message if you contact technical support personnel about your problem. An error code may help you know that the same problem is recurring. If you get an error 26 (Bad Program Launch), your application program may be corrupt. If you get other error numbers in the range 15-31, be suspicious of corrupt system software. The rest of the time your errors are likely to be hardware problems, conflicts, bugs or memory allocation issues. Occasionally you may run into errors that appear when you add or reconfigure SCSI devices.
Check for and eliminate duplicate System and Finder files on your system drive. If you want to store a copy of your working System or Finder on your hard drive, keep it in compressed form.
If nothing else has worked so far, you can try giving the System Folder a different name. Then move the contents to a newly created folder that you name System Folder. Bless it (make the Mac icon visible) by opening it and closing it even if you can see the icon already. If that fails, try dragging the System and Finder out of the System Folder, and then drag them back on top of the folder icon and drop them in again.
If you run System 7.5, be sure to install update 2. Whether it is necessary to update all the way to 7.5.5 is problematic. Apple's code word for crashing is "stability." System 7.5.5 is said to be more stable for the use of network printers and background processing. System 7.5.5 is less stable for memory allocation, since each program now needs more memory and it will not necessarily be allocated unless you go in and change the preferred memory allocation, program by program, extension by extension, ad nauseam. Read the "About System 7.5.5 Update" and decide for yourself what benefits you foresee, then read Macintouch for the downside. If you have a 68040 accelerator card, the "upgrade" can be a real disaster and is not advised. More detailed compatibility information for accelerators in general can be found on Shobaffum's Macintosh IIci Page. Migration to System 7.6 is never advised unless you are running a PowerMac. Migration to System 8 is only for machines with a built-in 68040 chip or PowerMacs. In these instances System 8 is said to be much more stable than any previous version of System 7.
You can zap the PRAM
especially if you have been getting error 10 or 11 repeatedly.
System 6 - press shift-option-command when opening control panel
System 7 or 8 - press option-command-p-r (simultaneously) continously
at startup until the machine has restarted at least three times. If you
have a PCI Mac, it is important to press the keys as soon as possible after
you press the power key so as to reset
both the PRAM and the NVRAM. Both TechTool
and PRAM-Reader
can store/restore a set of working PRAM values that you know are stable
(but not the NVRAM). The General Controls control panel can be moved out
of the Control Panel folder. It will run just fine as a stand alone application
and its normal location is thought by some to affect the robustness of
the PRAM. If your symptoms persist and you are convinced the PRAM is the
cause, you might try removing your battery for 20 minutes with the machine
unplugged. If your machine can't seem to hold onto the date or time PRAM
settings, it is time to check your battery. If your battery is ok, but
daily zapping of the PRAM is necessary to keep your machine running well,
PRAM
Auto-Restore can be used to restore your PRAM settings automatically
everytime you boot the machine. When a program crashes, unpredictable things
can happen. PRAMs, boot blocks, and disk directories can be corrupted.
System 7.6.1 - Error 11 will largely disappear with this newer system because
the bug that caused them to map wrong has been fixed. Under 7.6.1 the errors
will be reported correctly (e.g. as error 1 or error 2) and will not be
as likely to crash the machine. Before you do this install, however, read
the sobering Apple technical note that describes how such an installation
can wipe out your hard drive - Mac
OS 7.6 Blinking Question Mark After Install (3/97) and think twice
about the possible consequences. Rumor has it that the hard drive will
come back to life with a utility like Silver Lining. The daring can find
tips at MacFixit's special page: Troubleshooting
Mac OS 7.6.1
Power Macs are particularly susceptible to error 11. You might try SoftwareFPU from John Neil & Associates at (800) 663-2943 though it might make things run slower depending on which product you use. Installation of this and other JNA products can override hardware trapping of certain errors.
If you must use Open Transport instead of MacTCP, be sure that you have the very latest version or you may find that you will crash frequently with error 11 when accessing the internet.
Certain PowerMac models (like the 7500 and 8500) have a special cuda button on the motherboard that performs a PRAM reset that is even more rigorous than is possible with software. This button can be pressed if a software PRAM zap fails to help. If your screen is black, but the powerlight is on, this may bring your monitor back to life.
TWILIGHT ZONE: "We completely destroyed a 8500/120, simply by playing a 1 KHz tone using SoundEdit v1.6. While playing the tone, the system locked up, and upon restart, would not power on, and was totally dead."--Scott H. Richardson (a Systems Administrator for Motorola) via MacFixIt
If you operate under System 6 and get lots of bombs from the stack colliding with the heap, you might risk increasing the size of the heap with the Heaptool control panel or the FreeRAM FKEY. The heap under System 7 is no where near as troublesome. Mac OS Purge, Fixheap and Ramadillo are applications that reclaim unused heap space leftover by poorly written programs. Conflict Catcher allows you to increase the size of the system heap under System 7. Some of the technical issues are discussed in INITs, the System Heap and You.
ResumeToFinder and Bomb Shelter are control panel devices that may also allow you to save your work when a dialog box displays a bomb. This software adds a Resume button to the existing Restart button, so System 6 users have one more chance at recovery.
System Error Patch does not require you to press the button, it exits and logs the date, time and error to a file that you can look at later. This software has not worked for me under System 7.5. If your trouble is that you are responsible for a remote machine, the most useful approach is probably Autoboot, It reboots the machine, when an error dialog box appears. It can be used with Keep It Up, which checks to see if a critical application quits unexpectedly and relaunches it if needed.
In a final act of desperation you can reformat your system hard drive. If you have a second drive or even a removable that you can run from for a while, you may be able to learn whether the original hard drive is really the problem. Otherwise backup all your files and be sure you have a method to boot to a working drive with the software you will use to restore these files. A program or device that functions well to back up files under System 6, may not function at all under System 7 and vice versa.
IMPORTANT! Don't overlook recording any serial numbers that you may need to reinstall files or applications. Also, record the file count, so you can double check the number of files backed up with the number of files restored.
If you decide to reformat your hard drive, use the most current version of a good hard drive utility. For Apple hard disk drives, you may use what Apple supplies for the System that you are using, AppleHD SC Setup for early Macs and Drive Setup for Power Macs. For non-Apple drives programs like SCSI Director Pro, Silver Lining or Hard Disk Toolkit can be used. Once formatted, existing files are gone for good. If you use a backup program, do a trial restore of sample files to a test drive before you trash the drive, even if it is just a floppy.
Install fresh system software from locked factory floppies or a CD, then restore any remaining files needed for your work except any FileSaver or Prevention data files and/or any suspicious preference files. Test each program and extension to see that they all work.
If you are doing a first time install of System 7, be sure to check with vendors of any third party software or hardware you own for compatibility. Many out-of-business companies are unavailable to provide drivers or other support needed to run older products originally made for System 6 use. Be aware that System 7 was designed to run best on faster machines. It takes more memory, runs slower, is generally less responsive and crashes much more often than System 6. Many Macintosh users who have been forced to use Windoze at work notice immediately how much more stable it is compared to System 7. This is aggravated substantially on the web by the amount of crash prone software in use (e.g. Netscape).
The Safe Install utility from Apple will give you a list of phone numbers for the software products. The earlier Compatibility Checker that came with System 7.1 may give some additional advice about software that is known to be incompatible. In any case, System 7 will be much slower, less responsive and more crash prone that System 6. Some errors are more indicative of compatibility problems than others. The leading contenders are: Bus Error (1), Illegal Instruction (3), Numeric Overflow (6), Privilege Violation (7), Unimplemented Trap (12) and the ever popular Error Type 11.
Check 32! is a shareware application that looks to see if the 32-bit clean flag is set in your applications. I don't know of a hardware incompatibility list. Anyone who does is encouraged to e-mail it to this page. If you run just System 6 or System 6 and System 7 concurrently on different machines, see McOrphan.
When you run out of ideas and need to contact technical support, you may find that they would like the courtesy of a detailed system profile. Many profilers have come and gone over the years. Now Profile is bundled with Now Utilities and you may find TAA on a product disk from CE Software. TattleTech, MugShot, and TechTool can be found on the web in places like Shareware.com and InfoMac. The news that profilers were useful and valuable finally made it to Apple and with 7.5.3 came the first release of Apple System Profiler. ASP reports can only be generated on certain Powerbook, Proforma, and PowerMac models. I am not sure whether that means that these are Apple's most trouble-prone models or whether users of older models just aren't that important.
If you have a machine that crashes a lot and you have decided to live with it rather than have it fixed, you might like to try some software palatives. Safety Belt is a control panel from Alsis that helps you get running after a crash by telling you about files that were in use, but not saved when you crashed. Clipfolio keeps the contents of up to the last sixty paste operations in a file which you can read after a crash. The FileSaver control panel that comes with Norton Utilities helps keep track of files that are candidates for undelete. Detective tells you the name of the program that crashed. Norton Crashguard is a new component of Norton Utilities 3.5. When a crash occurs, CrashGuard displays a dialog box detailing the cause of the crash and gives users the option of attempting to save data from the application. The utility, which works only on Power Macs, keeps a log that includes the time and cause of a crash as well as the offending application.
If all this sounds too technical for you, unless you have a knowledgeable computer friend (not me), you will probably have to use a technical repair facility. Ask for an estimate of what it may cost to keep from being surprised later on. Don't forget to ask about the possibility of extended warrantee service.
Again, if you are an educational user or you have a new
machine that is under 90-day warranty, Apple can be reached for their free
advice at (800) SOS-APPL. Their Customer
Support Program options are listed in a press release explaining
the termination of their free telephone support. Good Luck.
Troubleshooting
Links
Macintosh Guide - Clear answers to many common questions from Yale
General Troubleshooting:
From the horses mouth: - More selections from Apple's TIL
Freezes:
Putting together the pieces:
Extensions and Control Panels:
Error Codes:
Viruses:
Batteries:
Data Recovery:
MacinSearch
The Basic Crash Course:
This summary lists the most common sources of crash troubles for machines that have been stable for some time--no recent virus opportunities, no new fonts, extensions, system software, applications, patches or hardware added recently.
When does this happen-
1) before the extensions load (more than likely a Hardware Issue)
If you get a failure tone or a sad Mac, turn off the power, and simply try again. If this has no effect, you may want to pull the external SCSI cable, boot, shutdown, and the reinsert cable. If you still get a failure tone, boot to a floppy and run your favorite disk doctor. If you can boot to a floppy, but still have a problem booting to the hard drive you can update the boot blocks.
2) during extension loading (probably one of many possible Extension Conflicts/Bugs)
Restart your machine with extensions off using the shift key. If turning the extensions off eliminates the crash, try turning on just the Apple extensions, if that doesn't work look for corrupted preferences or run your favorite disk doctor to see if it finds any corrupted files or directories. If this doesn't zero in on the culprit, try selective exclusion of extensions looking for a conflict and replace any faulty files from factory media. Failing that, you may want to Zap the PRAM (and the NVRAM if you have a PCI Mac).
3) after extensions load when the finder starts (check Finder/Desktop Integrity)
You can delete the Finder Preferences file and rebuild the desktop. The most direct way is to restart and hold the command and option keys down after the extensions have loaded, until asked if you want to rebuild the desktop. Click yes. Other, possibly better, ways are detailed elsewhere. If you freeze with a blank menu bar at startup, hold down the option key right after the extensions have loaded. If during these attempts, you have never been able to get to the desktop, run your favorite disk doctor from a bootable floppy. Replace the System and Finder if all else has failed.
4) after the desktop appears (see When you get to the Desktop)
The most important thing to do when you get to the desktop
is to run your favorite disk doctor program. Both directories and files
can become unexplainedly corrupt and will need occasional repair or replacement
from your backups. If the program says it fixed something, run it again
and see if it really did. If it didn't, consider booting from an emergency
floppy and running it again.
If your crashes are applications specific, just deleting the associated preferences file may be sufficient to fix your problem. Otherwise, it is best to reinstall the software from locked factory media after verifying that you have sufficient memory allocated. Troubleshooting Mac Applications offers a cribsheet approach.
If these short tips don't suffice, explore the more detailed sections for additional ideas to try.
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