Run Apple Hardware Test
When you purchased your Mac, the box should have included a CD or DVD with an application called Apple Hardware Test. Depending on when you bought your computer, this could be an independent disc, or it may be included on the Mac OS X Install Disc. (Look for tiny lettering on the disc that says “To use Apple Hardware Test, hold down the Option key as the computer starts up,” or words to that effect—your disc may specify a different key, for example.) Find this disc now. (I’ll wait while you root through your attic or basement to find it hidden in the bottom of a box somewhere.)
Back already? Super. You have in your hands a special program. Apple Hardware Test can run only when you start up from the CD or DVD it came on; don’t bother trying to copy it to your hard disk. This program performs a series of diagnostic tests on your Mac’s hardware, including the AirPort card, logic board, hard drive, RAM, modem, and video RAM. It doesn’t repair anything, and it doesn’t look for problems such as directory errors that are the province of Disk Utility (see Run Disk Utility, below ). But it can identify subtle hardware defects that could later lead to serious problems. Whether your Mac is fresh out of the box or years old, you owe it to yourself to make sure its major components are in good health before upgrading to Leopard, and this is the easiest (and cheapest) way to do so.
Note: Apple Hardware Test isn’t the only tool that can check your RAM. Among the other utilities that can do this are TechTool Pro ($98), Memtest OSX ($1.39), and Rember (free). I’ve personally had bad RAM that Apple Hardware Test could identify while these others could not, whereas other Take Control authors have had the opposite experience. Your mileage may vary!
To run Apple Hardware Test, follow these steps:
I recommend running the test again after installing RAM or any other new hardware inside your computer, or if you begin to have inexplicable problems that ordinary disk utilities do not solve.
Run Disk Utility
You know the saying: “If it ain’t broke, don’t fix it!” With computers, though, things can be broken without manifesting obvious symptoms. You can nip many such problems in the bud with a simple procedure that looks for, and fixes, common disk errors that can crop up over time without your knowledge.
To repair your disk, follow these steps:
Select a volume (other than the startup volume) on the left, and then click Repair Disk.
Note: You can’t repair the disk from which Mac OS X is running (or the disk from which Disk Utility is running, if it’s not the same one); that would be like performing brain surgery on yourself. You can, however, verify the disk (by clicking Verify Disk in Step 4) to determine whether there are any problems that Disk Utility could repair.
/Applications/Utilities; if you started from a Mac OS X installation disc, click through the language selection screen and then choose Utilities -> Disk Utility.
Disk Utility looks for common errors and repairs them if possible. Ordinarily, it displays a message saying that repairs were completed or that no repairs were necessary.
In the (rare) event that Disk Utility encounters a serious problem it cannot solve, you may need to use a commercial repair tool such as DiskWarrior ($80).
[ Joe Kissell is Senior Editor of TidBits, contributes frequently to Macworld , and has written numerous books about the Macintosh, including many popular Take Control ebooks. His latest is Take Control of Upgrading to Leopard: Early-Bird Edition ( TidBits Publishing Inc., 2007). ]