Macintosh crash tips

A general diagnostic procedure for Macintosh freezes and crashes

CAUTION: If you don't backup your data, your worst nightmare may be awaiting you.

Save Your Work

If you learn nothing else from this chapter, learn this: With depressingly few exceptions, if you get a system freeze or crash while you are working on a document, any unsaved changes you made to the document are lost-forever! So remember to press the Command-S keys whenever you pause for a moment. The few seconds it takes to save your document can save you hours of frustration down the road.

Back Up Your Work

Even if you saved a document, danger still lurks. A file could become hopelessly corrupted or a hard disk crash could wipe out the entire contents of your disk (don't get too alarmed; this happens only rarely, but it does happen). To prevent thoughts of suicide at such times, make sure all of your data are backed up to some other location.

Crash vs Freeze vs Hang

After a crash your machine is useless until you restart, the keyboard has no effect, the mouse pointer will probably not move, the clock is not ticking (it is handy to have the seconds displayed on your menu bar clock to see this). During a freeze, your mouse will probably continue to work normally, the clock will be ticking away, but the keyboard will probably act as if it has been disconnected. If you hear the drive churning away, your computer may just be really busy doing something. A hang is related to a peripheral, your computer will freeze or possibly crash when some device is turned on, or when software tries to access it or perhaps when a removable cartridge is inserted. Sometimes a hang will just go away when you disconnect or turn off the offending item, other times you will have to restart.

Simple Application Freezes

The Frozen Mac

You're merrily working along when WHAM! everything halts. If you are lucky, the cursor may still move when you move your mouse, but that's it. Pressing keys does nothing, clicking the mouse button does nothing. Nothing does anything. Your Mac screen is now a frozen still life. Here's how to thaw it out.

Force Quit

  1. Before doing anything else, Press Command-S. If you had unsaved work at the time of the freeze, this might still save it (doubtful really, but worth a try) even though it won't help you recover from the freeze.
  2. Next, press Command-Option-Escape. This is called a force quit. With some luck (and you can't be having a lot of luck here or you wouldn't have had this problem to begin with), you will get a message with a button that says "Force Quit." Now click the Cancel button. I know. Officially, this should do nothing at all. But occasionally it wakes up the Mac and gets things rolling again. I also have had similar success (even before doing a Force Quit) by moving the cursor to the desktop and clicking on an icon there and then switching back to the frozen application. If this works, immediately save all your data. Then, to minimize the chance of another freeze returning all too soon, restart your Mac.
  3. If, as is more likely, your Mac is still frozen, click the Force Quit button. You still have to hope for some luck here, because this button only works maybe 70 percent of the time. If it fails, either nothing will happen or the situation will get worse (such as the cursor, which had been responding to your mouse movements, no longer doing so).
  4. If the Force Quit succeeds, the program named in the Force Quit dialog box (presumably the one most responsible for the freeze) will quit and you will most likely be dumped into the Finder. Your Mac should now be behaving fairly normally and any work you had going in other programs (aside from the one you quit) should still be available to be saved. As for whatever unsaved work you had in any documents you were working on in the application that quit, well, my condolences to you.
  5. Once you are back in business and have saved all that could be saved, select Restart from the Finder's Special menu. This is just to be safe. You can continue working without restarting, but you are courting disaster. Another freeze is likely to occur soon, especially if you return to the application you force quit from.

Reset

If the Force Quit failed at any point in the previous steps (or you were never able to get the force quit alert box at all), press Command-Control-Power (the Power key is the one on your keyboard with the triangle symbol on it). This is called a reset. On most recent models of Mac, this should restart the Mac.

If this key combination does nothing, it is probably because you have a Mac model that uses a physical reset button somewhere on the Mac itself, rather than using this key combination. It is usually one of a pair of buttons on the front or rear of the machine (If your press the "wrong" one of the pair of buttons, don't fret. Whatever happens, press the other button next and the restart will happen.

Finding the exact location of the reset button can be a bit tricky, as Apple finds it amusing to keep finding new places to hide it. If you can't find it, check with the documentation that came with your Mac. Otherwise, you can simply turn the Mac off and back on again.

After Resetting

After resetting, you may get a message during startup that says that your did not shut down the Macintosh properly. This is true. Shutting down by any method other than selecting on onscreen Restart or Shut Down command is considered improper. But don't worry. It doesn't mean anything bad has happened. Just dismiss this message and proceed as normal. Still, if you want to prevent this message from reappearing the next time you have a problem, go to the General Controls control panel and uncheck "Shut Down Warning."

After you reach the desktop, you'll probably find a folder called "Rescued Items" in the Trash. If you had some unsaved work that was lost in the freeze, there is a rat's whisker of a chance that a file in here contains the lost data. To find out, open the file(s) in the application(s) that you were working on at the time of the crash. Most likely, you'll find that the files are worthless. It's not a coincidence that these files are in the Trash. It's a hint as to what you should do with them!

Finally, you're back in business and your Mac should now be running fine again. But what if the freeze returns the next time you do whatever caused it to occur the first time? How do you figure out what is causing the freeze, so that it doesn't happen again? The depressing answer to that question is that there is no easy answer to the question. The happy answer is that this is really not your problem. Just report the crash incident to the lab manager and resume your work!

System Crashes and Bombs

If you're wondering what could be worse than a system freeze, here's one answer: a system crash (or, as it is sometimes called, a bomb). Typically, an alert box appears with an icon of a bomb in it. The message starts off by apologizing for the intrusion, "Sorry...." But I doubt if that makes you feel any more kindly toward it.

Don't worry, the bomb icon does not mean your computer is in danger of exploding. You may laugh, but I know someone who, after getting their first bomb alert, refused to touch their computer for the next several hours, until she could get a hold of me on the phone, fearful of what might happen if she tried to use it further.

As with the freeze, the bomb puts an end to whatever you were doing. Actually, dealing with bombs is quite similar to dealing with freezes, except that the force quit option is so unlikely to ever work, I wouldn't even bother trying it (the Restart button that may appear in the bomb box also only works sporadically).

Your first step should be to restart your Mac. If you are lucky, the system crash won't repeat. If it does, contact the lab manager.

What Are All Those Error Codes Anyway?

When you get a system crash or an unexpected quit, you'll often find that the accompanying error message lists a code number (such as "an error of Type 1" ) or an equally mysterious expression (such as "unimplemented trap" or "FPU not installed"). You may well wonder what the heck does all of this mean?

More printer's ink has been wasted answering this question than any other troubleshooting question about the Macintosh. I have seen books devote dozens of pages listing the meaning of almost every imaginable error code number. The information in these tables typically isn't any easier to understand than the error codes themselves. And they almost never contain any useful advice as to what to do if you get a specific error.

The plain truth is that these messages are meant as guides to programmers who routinely get these messages while debugging their software. They have little usefulness for the rest of us.

Not Enough Memory

You go to launch an application and you get a message that says: "There is not enough memory to open [your application]." This is one of the most common problems a Mac user faces-especially since application developers seem to double the minimum amount of memory their programs require every time they come out with a new version.

What can you do about this? First, it helps to understand exactly why you got this message and how much more memory you need to get the application to open. To do this, click on the application's Finder icon and select Get Info from the Finder's File menu (Command-I is the shortcut). From here, note the Minimum size listed in the Memory Requirements box. Next, while still in the Finder, select About This Macintosh from the top of the Apple menu. From the box that appears, note the size of the Largest Unused Block. If this number is smaller than the Minimum size, you don't have enough memory to open the application. What to do next depends upon how much more memory you need and what you currently have running on your Mac. Here are some guidelines that should get you through most memory hassles:

  1. Quit all open applications. Close all open Finder windows. Actually, the alert message you get, indicating a lack of available memory, probably advises you to do this. So you shouldn't need me to tell you. Still, it's good advice and worth emphasizing. It frees up additional memory, which may be all you need to open that pesky application. It should also resolve problems with memory fragmentation (where unused memory is divided into small chunks rather than one large one).
  2. If you still can't get the program to open, go back to the About This Macintosh window and sum the Largest Unused Block and the System Software allocations. They should add up to approximately the same number as the Total Memory. If not, you may have a memory leak (where an application does not release its memory allocation after you quit the program). Programs that make use of shared library extensions may result in a similar problem. Whatever the cause, the surest way to fix it is quite simple: restart. If that seems too time-consuming, you can try a Force Quit (press Command-Option-Escape). This usually works too, although it may leave your Mac in a state that is more prone to system freezes and crashes.

Documents That Won't Open

Another all too common problem is when you double-click a document icon to open it from the Finder and you get a message saying that the document would not open because the "creating application could not be found." Most of the time, the document is just fine. Run through the following checklist, and you will almost certainly succeed in opening it:

Can't Empty the Trash

The Trash can is bulging, but when you go to empty it, it refuses to cooperate. Calling your local sanitation department won't help you. However, one of the following solutions is almost certain to fix this glitch.

When Programs Don't Work

Basically, this is a catch-all category that covers those occasions when some command or some feature of a program doesn't work the way that it should. To be honest, there are dozens of possible explanations for why this might happen. Still, most of the time you can simply quit the problem program. If this does not cure it, try restarting the computer. Sometimes programs have memory problems ("memory leaks") that will tie up system resources so badly that only a re-boot will clean everything.

Otherwise, there is probably some bug in the program you are using. Contact the vendor for assistance. In the meantime, although not an ideal permanent cure, turning off one or more features of Apple's system software can sometimes act as a work-around. The most common culprits here are: Virtual Memory, Modern Memory Manager, AppleTalk and File Sharing.

Unreadable Floppy Disks

If you insert a floppy disk and the Mac says it is unreadable and offers you the chance to initialize it, don't panic-and don't initialize it. As long as you don't erase the data on the disk, the odds are generally good that you can recover the data, even if the disk itself turns out to be unsalvageable.

Eject the disk. If it isn't already write-protected, do so now (slide the plastic tab on the disk until you can see through the hole). Once it's protected, try inserting it in another Mac (if you have one available)-often the alignment of the heads in two floppy drives is just different enough to make a disk that's unreadable in one drive readable in another. If the disk was last used in a Mac other than yours, try that drive in particular if it's nearby. If another drive can read the data, copy the files to the hard drive and then to a new floppy.

Some newer models of Mac have trouble reading mass-produced 800K disks. If this happens, and you don't have another Mac around that can read the disk, starting up with extensions off or zapping the PRAM may solve the immediate problem.

To read PC-formatted disks, make sure PC Exchange is installed (it comes with System 7.5).

If the unreadable disk is an HD (1.44MB) disk that you are inserting into an old 800K drive (such as on a Mac Plus), the drive can't read the disk. You will need to use a newer SuperDrive floppy disk drive (used on all current Mac models).

Otherwise, it's likely that the disk really is damaged. If you want to try to recover data from the disk, your best bet is to first make a copy of the disk using Norton Utilities' Floppier or MacTools Pro's FastCopy. The copied disk will probably mount now with most or all files on it accessible. Copy the files to your hard drive. If the copied floppy disk is also unreadable, or you still can't locate or open a particular file, try using file recovery features of Norton Utilities or MacTools Pro. In any case, when you are done with your recovery, discard the unreadable disk. Don't bother trying to reformat it and use it again. It's not worth the risk.

Occasionally, a floppy disk is unreadable because the floppy disk drive itself is dirty or malfunctioning. Disk cleaning kits manufactured by 3M (available separately or as part of MicroMat's DriveTech software) may fix this. From my experience, this will only rarely help, but it's cheaper to try this first than to take your drive in for an unneeded repair.

Floppy Disk and CD-ROM Disc Jams

You selected the Eject and/or Put Away commands but your disk refuses to budge. Try each of these in turn until one works.
  1. Quit all open applications. Try again to eject the disk, typically by dragging the disk icon to the Trash icon.
  2. Turn off file sharing (especially if it is a CD-ROM you are trying to eject). Try again to eject the disk. (Turning off file sharing should not be necessary if you are using System 7.5.1 or later, but try it anyway).
  3. For floppy disks, press Command-Shift-1.
  4. Restart and hold down the mouse button. Wait for the disk to eject.
  5. For CD-ROMs, restart and immediately press the drive's eject button. Note that this button will not eject a disk at any other time. Normally, the button only opens the tray when there is no disc in it.
  6. If all else has failed, contact the lab manager.

Some floppy disk jams can be caused by a floppy disk with a bent metal shutter or a partially unglued label. Check for these problems before inserting the disk.

If your keyboard or mouse goes dead, determine first if it really is a machine freeze or if only a mouse or keyboard hardware malfunction. 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! Technically speaking, 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 unplug things without shutting down first.

One trick to outsmart mouse frost is to be able to Save in an application using a keyboard command-S (the command key is often referred to as the "open apple" key), very useful if just the mouse dies. 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. You can hold down the command and option keys while pressing the Escape key to forcibly quit an application. However, Command-option-escape doesn't always work.

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, contact the lab proctor on duty immediately.

After rebooting, you may notice a folder called Rescued Items in the trash. It is usually empty or contains useless material.

If the freeze only happens only while printing a document, there may be insufficient memory to run the Print Monitor. You can try shutting down unused programs (don't just hide them) to free more memory

If you are unusually low on disk space, your machine may begin to freeze sporatically. Unknown to the user, many programs create invisible temporary scratch files as part of normal functioning. If there is not enough disk space to create these files, your computer may freeze or even crash as it slips into desperation. If this seems to be the case, restart your machine.

No matter what the circumstance, always report any freezes or crashes to Dr. Riedel at mriedel@rci.rutgers.edu.

Summary of Keyboard Commands

Save your data Command-S
Cancel a stuck dialog box Command-. (period)
Close a frozen window Command-W
Quit a frozen application Command-Q

 

This information originally appeared at http://www.zplace.com/crashtips/