Appledoc First Aid For Older Macs.

When your Mac starts crashing, bombing, hanging, whatever, try the following; some are just shortcuts, others often solve the problem.

Keys on the keyboard

The "command" key is the key with the Apple logo and/or the stylized cloverleaf symbol. The "control" key is different; it says, well, "control." Don't confuse them, or you will be chagrined. The "power" key is the key (not found on all keyboards) with the triangle symbol.

Force-Quit

Try pressing option-command-escape at the same time. If it brings up a box that says "Force <whatever> to quit? Unsaved changes will be lost" then say yes (at this point, your changes are lost anyway). Most of the time this does NOT work, and it just crashes again. If it does work, the program will quit, and everything will seem okay. But you should restart (from the "Special" menu) before you do anything else. When this works, it's nice because sometimes you can save changes in other programs before you restart, and it's a little better for the system than doing a harder restart (i.e., the Three Finger Salute or flipping the power switch. See below.)

Restart (the Three Finger Salute and other methods)

Crashing can be a result of cluttered or corrupted RAM. Restarting clears the RAM. To restart from a crash, press control-command-power simultaneously. If that doesn't restart it, look for a little triangle-symbol button on the Mac itself (not the keyboard). It should be next to a little circle button; sometimes these buttons are on the front, sometimes the back. Sometimes they're recessed, and you have to use a paper clip or something to push them. Press the triangle one. If even THAT doesn't work, turn it off and on again, but that should always be the last resort because over time it will shorten the lifespan of your power supply and just generally de-stabilize things.

New annoying feature of USB Macs: During a crash, your Mac completely loses the ability to comprehend the existence of a keyboard. Get used to hitting the triangle button on the front (or on the side, for you poor iMac owners) a LOT.

Interrupt

This is the little round button next to the triangle one on your Mac. Programmers use it to interrupt a program and type code to alter/debug it. However, in SOME rare cases, you can use it to escape from a crash. It works maybe once out of 8 times. Press it and you should get a blank box with a > prompt. Now you can enter something known as a finder recovery string. Type

G FINDER

exactly as it appears, with a space between G and FINDER. Then hit return, and if you're lucky, it'll take you to the Finder and you can continue whatever you were doing. But again, you should restart now, to clean everything up.

Rebuild the Desktop

The desktop file is an invisible file that helps the Mac remember the directory hierarchies, the appearance of icons, and other stuff. Sometimes it, too, gets corrupted (or infected by a minor virus), and this can affect the operation of some programs. To rebuild the desktop, restart the Mac and hold down the option and command keys. Keep holding them down until you get a message that asks you if you want to rebuild the desktop. Say "okay" and let it finish. Don't worry about the comments in the info windows, nobody uses them. Newer versions of the system software save the comments anyway.

Zap the PRAM

PRAM stands for Parameter RAM, which is a chunk of RAM that (you guessed it) gets corrupted occasionally. However, simply restarting doesn't clean it up because the Mac's internal battery saves it even after you restart.To "zap" it (which just means clear it), restart the Mac and immediately press and hold the option, command, P, and R keys simultaneously. Hold them until you hear a second AND third startup "bong." Then let go and let it boot up from there. Whenever you zap the PRAM, some settings are lost, like the mouse speed and clock time, and you have to go into the Appletalk (or Network if you have older software) control panel and set it back to "Ethernet" if you're on Ethernet (see below for more info about the network.)

Throw away the preferences

(Quit the program before you do this). If a particular program is acting weird, like printing garbage instead of text, or the window is too big for your monitor (meaning that you can't reach any of the scroll bars or zoom box!) then try pitching the Prefs file. Know why? That's right! It gets corrupted just like everything else. In the System Folder there's a folder called "Preferences." In that, there are a bunch of small documents which belong to programs you use. They usually contain the name of the program. Each application creates a prefs file which remembers basic settings, like size of the window in the program, or the location of palettes, or whatever. You won't wreck the program by trashing that file. The program will make a new, hopefully clean one next time you run it.

Rebooting with Extensions off / invoking Extensions Manager at startup

Crashes on startup are often indicative of a dreaded Extension Conflict. Hold down the Shift key until the startup screen is visible (it'll say "Extensions disabled" or "Extensions off"). If you had just added a new control panel or extension when the problem occurred, take it out, because it's probably the culprit. If you don't suspect any particular extension, always try removing the third party ones first ("third party" means that they didn't come with the system software, i.e., they're not made by Apple). In this context, by the way, "extension" includes both extensions and control panels. Those cute little things that let you customize the Mac's appearance are often buggy, and they try to use the same chunk of RAM as another program or something like that; this makes the system crash.

In System 7.5 and up, you can use the Extensions Manager control panel to turn off anything that's not part of the basic system software. To open EM at startup, hold down the spacebar (this may only work on 7.6 and up, I'm not sure). Then choose another set, or turn off what you think is bad. You can do Extension Manager's job for it if you want, simply by moving things out of their respective folders and into their "disabled" folders. That's all EM does when you check or uncheck things. If Extensions Manager whines about there being two copies of something, then delete the older one (look at the version numbers). If they're the same version, delete whichever one you want.

SCSI ID and SCSI Termination

If you have peripherals attached to your Mac (like extra hard drives, a scanner, a Zip drive, a Syquest, an external CD-ROM, etc.) make sure that they have all been assigned a unique SCSI ID number. There's a little switch on the back of the device that lets you choose a number from 0 to 6. Keep in mind that ID 0 is always the internal hard drive, and if you have an internal CD-ROM drive, those are almost always set to 3. (The computer's CPU is 7, and you're never given the choice to use that number.) If you have two devices set to the same number, you're guaranteed problems. If all the numbers are unique, but you're still having problems, check that the last device in the SCSI chain is correctly terminated. Zip drives and some other devices have internal termination (look for a switch on the back) but usually you'll have to use a big blocky plug to fill up the empty slot on the last device. If your last device only has one plug, put the terminator between the cable and the device. Some Powerbooks require double termination! Check the manual. If nothing else works, try switching the order in the daisy-chain or using different cables; some have more shielding than others (they will be thicker and less flexible, and also more expensive, typically.) Getting multiple SCSI devices to work together is basically voodoo.

Booting from a diskette/CD/other volume

To boot from a floppy disk, just insert it into the drive and turn on the Mac. It will automatically boot from the floppy, as long as the floppy is bootable (i.e., has a viable system on it). By the way, if you have a floppy where it gets partway through the startup process and then crashes, then you hit restart and it tries to boot again, and crashes again, etc. you can get out of this loop by restarting and holding down the mouse button until the floppy ejects. To boot from a CD, insert it and turn on the computer; on some newer Power Macintosh models, you have to hold down the C key during startup, but on the older ones you'll have to use the key combination explained below. To boot from another volume (like a second hard drive, Zip, or Jaz disk), connect the drive (make sure its SCSI ID is unique) and turn it on. Then turn on the computer and hold down shift, option, command, and delete until it starts booting from the external device. Anything you want to boot from must have a compatible system already loaded onto it; the system CD that came with your computer will always work, or you can copy your system folder to a Zip or external drive for future emergencies.

Giving more memory to a program

Sometimes programs crash because they run out of RAM. You can allocate more memory to a program by clicking on the icon of the application (make sure it's not running while you do this) and selecting "Get Info" from the File menu. There are two boxes at the bottom of the window, "Minimum" and "Preferred." Make "Preferred" larger than it was. Naturally, you can't hand it more memory than your machine actually has; in the Finder, go to the Apple menu and select "About this Computer." Look for "Largest Unused Block" -- don't set the memory any higher than that number. And don't come too close to it (within about 1000k), for reasons I'm not going to explain here. Keep in mind that if you don't have much RAM, and you give most of it to one or two programs, other programs won't want to run at the same time. You'll have to quit one to use the other.

Reinstall the system / Clean install

This is kinda drastic, but it's also a pretty effective fix. Take your system CD or floppies and boot from them. Reinstall everything from the installer program. The installer knows to replace the basic software without deleting your extra extensions, so you don't have to go grab everything off of Public again. This is a simple reinstall, or "dirty install," because it retains what may be problematic garbage from your old system folder. However, the things that get replaced are often the ones causing grief, and you don't have to start over from square one getting your settings all configured the way you like.

A "clean" system install makes a new system folder and renames the old one. Hold down shift-command-K in the Installer. This will bring up a box asking you if you want to do a clean install. (On newer OS versions, "clean install" is an option in the "options" section.) The advantage of doing a clean install is that you can drag only certain extensions and control panels into the new folder to test them, which might be easier than dragging all the other ones OUT of the old folder. But more importantly, doing a clean install prevents the risk of retaining a corrupt System file; if the file is corrupt and you install a new one on top of it, using the conventional install option, the installer might write around the corrupt bits and bytes, so you'd be right back where you started.