CPR for startup problems
What strikes the most fear into the hearts of Mac users? When the computer fails to start up at all. It’s hard not to wonder if you’ll ever see the contents of your hard drive again—especially if you also failed to back up your drive.
If your Mac seems to start up normally but stalls at some point before the desktop appears—indication that the problem isn’t with your monitor or your power—use these guidelines for reuniting with your data. Try each step in turn until one succeeds:
Step 1: Patience Sometimes the Mac will take an unusually long time to start up. Take a deep breath, head to the kitchen, and wait awhile to see if the Mac rights itself.
Step 2: Restart Again OK, you got a cup of coffee and read the newspaper’s front page, but your Mac still hasn’t started. Try restarting one more time. Things often work better the second time around.
Step 3: Do a Safe Boot Restart and immediately hold down the shift key until the sundial icon shows up at the gray screen to initiate a safe boot. Eventually, the login screen appears with the words “Safe Boot” below the words “Mac OS X.” This means you have initiated a shotgun collection of potential fixes. OS X runs a disk repair command, deletes potentially corrupted font cache files, disables files called extensions (located in the System folder), and prevents items in your Login Items list (in your Accounts system preferences pane) from loading.
If you succeed in getting your Mac to start up in this minimalist mode, restart immediately (this time without activating Safe Boot). The disk repairs and cache cleaning alone may have fixed the problem.
Step 4: Investigate Your Login Items If you’re still in trouble after a post-safe boot restart, it’s going to take some detective work to figure out what’s going on. For example, if the crash occurs after you’ve logged in to your account (and the desktop background has appeared), the most likely cause is a Login Items conflict.
To check for this, go to the Preferences folder inside the Library folder of your user folder. Locate the file named “loginwindow.plist” (not “com.apple.loginwindow.plist”). Now, make a copy of the file and store it in another location (such as your desktop).
Next, go to the Accounts system preference pane, select your account name, and click on the Login Items tab. Select the top item in the list and click the minus-sign (-) at the bottom of the Login Items window. Next, log out (Apple menu: Log Out user name) and then back in. Continue removing items one by one until the crash stops occurring. When it does, it’s a good bet that the login Item you last deleted is the culprit.
At this point, replace the active loginwindow.plist file with the copy you made. Return to the Login Items window in Accounts. Your complete list of login items should be back. Delete just the likely culprit item, log out, and log back in.
Step 5: Repair the Disk Mac still not starting up properly? When you do a safe boot, OS X attempts to repair your disk, but it offers no feedback as to what happened. You don’t know if it found and fixed problems or if it ran into problems it couldn’t fix. If the safe boot fails to fix the problem and login items have been ruled out as a cause, try using Disk Utility’s First Aid to repair the disk (see Seeking First Aid for instructions).
Step 6: Disconnect Peripherals If you’re still having problems, try disconnecting all USB and FireWire devices (except your Apple-supplied keyboard and mouse). Restart the Mac yet again. If you can start up, you may have had a conflict between OS X and one of the disconnected devices.
You may be able to reconnect all the devices and use them, but if you leave them connected, your Mac may fail to start up the next time you try. The only way to cure this problem is by updating the device’s driver software or firmware. (Firmware is the set of programming instructions stored on the hardware itself; it remains unchanged unless specifically modified by a firmware updater utility.) Check the company Web site for details.
Step 7: Reset PRAM Restart the Mac yet again. This time immediately hold down the Command-option-P-R keys until the Mac chimes a second time. This resets the information in the Mac’s Parameter RAM (PRAM) to its default values, which can solve certain startup problems. PRAM is a special area of RAM where data is retained even after shutting down the Mac. PRAM stores an assortment of systemwide parameters, such as time zone setting and speaker volume.
Step 8: Reinstall OS X If all else has failed, start over with a fresh installation of OS X. This is often the only cure if your symptom is a persisting blinking question mark icon at startup, which indicates that your Mac doesn’t believe there’s a valid version of OS X is installed on your drive.
Treat panic attacks
It’s an ominous sign indeed: your screen just turned a shade darker and a message appeared—in several languages—informing you that you must restart your Mac. Your Mac is suffering from kernel panic. Despite the name, there’s no need to panic if you experience it. Just follow these five steps:
Step 1: Restart First, restart your Mac as requested. Near the end of the startup, a “this application has unexpectedly quit” message will appear. Don’t worry: your Mac is merely informing you that OS X itself quit unexpectedly prior to your restart.
Step 2: Check for Updates Like program crashes, kernel panic problems often vanish after a restart. If not—and if the onset of the panic is linked to a specific program—there’s almost certainly a fatal bug in that software. Contact the maker for an updated version or for technical support.
Step 3: Ax New Hardware Have you recently added RAM or a PCI card to your Mac? Regard such additions with suspicion, especially ones that add a kernel extension with the word Driver in its name to your Mac’s /System/Library/Extensions folder. These can be potential sources of kernel panics. If you recently added a card or peripheral to your Mac, try removing it to see if that eliminates the panic.
Step 4: Try a Safe Boot If the kernel panic occurs at apparently random moments or during startup, try a safe boot. Restart and immediately hold down the shift key until the sundial icon shows up at the gray screen.
Step 5: Reinstall OS X If the safe boot succeeds but kernel panic strikes again when you boot normally, a file in the /System/Library/Extensions folder is generally the cause. The file was probably installed by a third-party program. The simplest approach here is to reinstall OS X via an Archive And Install, and then reinstall your third-party software only as needed until you find one that triggers the panic.
Find more help
This guide to OS X first aid should help you through most common crises. But if your Mac is still sickly, your next step is to check out Apple’s Support page or a general troubleshooting site, such as MacFixIt. It also never hurts to Google some relevant search terms and see what you get—sometimes you’ll find creative cures this way.
If home remedies don’t work, it’s time to call the doctor. New Macs come with 90 days of telephone support and one year of service coverage. Apple’s extended warranty—AppleCare Protection Plan—costs $149 to $349, depending on your Mac model and gives you three years of telephone support and service. Call 800-275-2273 or visit your local Apple store for help.