OS X First Aid

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Cure application crashes

Just as unwelcome as the application freeze is the application crash. In this case, you’re not trying to force a program to quit; you’re trying to prevent it from quitting on its own. When an application crashes, you typically see a dialog box informing you that it has “unexpectedly quit” (see “Unexpected News”). As with application freezes, the good news is that these crashes rarely bring down an entire Mac—they usually affect just one application. But you’ll still want to end this ailment. Try these methods, one by one, until the problem disappears:

1. Relaunch The “unexpectedly quit” dialog box contains a Reopen button. Click on it to launch the application again. With luck, the crash will not recur.

2. Safe Relaunch If the crash does happen again, curse your luck and wait for the dialog box to appear again. You’ll notice that it’s slightly different now—there’s a Try Again button instead of a Reopen button. Click on it to launch the application in Safe Relaunch mode. When you do this, OS X replaces the application’s preferences file with a new file.

Applications use preferences files to store the changes you make to application settings—via the Preferences dialog box, for example. But if preferences files become damaged, they can precipitate a crash. (Preferences files are stored in your user folder /Library/Preferences and are typically named after the application they belong to—com.intuit.quicken.plist is Quicken’s, for example.)

Unexpected News Here’s what you’ll see when an application crashes. Click on Try Again to launch it in Safe Relaunch mode. OS X will disable the application’s preferences file and replace it with a new default file.

If Safe Relaunch eliminates the crash, quit the program (File: Quit). At this point, another dialog box will appear and ask whether you want to keep the new settings or revert to the original ones. Keep the new ones and reset any custom preferences—if this puts an end to the crashes, it’s a price worth paying. If you decide you want to go back to the original settings—perhaps because you discover that switching preferences files ultimately didn’t help—you can still return the original .plist file to active duty (see “What’s Your Preference?”).

If a Safe Relaunch doesn’t stop the crashes, it’s time to move on to a time-tested set of potential fixes. These are worth trying not only for crashes but also for almost any other odd symptom you may confront. Try them in order until one works.

3. Restart Your Mac Select the Restart command from the Apple menu. It’s amazing how often this simple act resolves a problem. If the crash is so bad that you can’t get Restart to work, press and hold your Mac’s power button until the machine shuts off. As a last resort, turn off your Mac by unplugging the power cord.

4. Check for Conflicts and Bugs If the troubled application is not Apple software, make sure it doesn’t have a conflict with the version of OS X you’re using. For example, if you just updated to a new version of OS X, you may also need to update the problem program. Check the company’s Web site for details. While you’re there, check to see if the site has a support section. You may find that your problem is common enough that the company has posted a solution.

What’s Your Preference? Did you select to shift to new settings after a Safe Relaunch of a crashing application, but now want the original settings back? You’ll find them stashed away in your user folder/Library/Preferences, labeled with the .saved extension. To return to your old settings, delete the new default preferences file and remove the .saved extension from the old one.

5. Log In as a Different User You’ve installed new programs and you’ve tweaked preferences—is it one of the millions of changes you’ve made to your sys-tem that’s giving your Mac a stomachache? You can find out by logging in as a different user. If you’ve never created a second account, now is the time to do so.

If the crash doesn’t occur when you’re logged in to the other account, the crash’s cause is a file in your user folder, rather than a more general issue with OS X. Accept this as good news, since it usually means that the problem can be fixed without something as drastic as reinstalling all of OS X—or erasing your entire drive.

The cause is most likely a corrupt or conflicting file somewhere in your user folder’s Library folder—either a preferences (.plist) file, a font, a cache file, a plug-in, or some other support file (often found in the Application Support folder). You can use utilities to isolate the specific cause. For instance, check for corrupt fonts with the Validate Font command in OS X’s Font Book utility, use Jonathan Nathan’s Preferential Treatment to identify corrupt .plist files, and delete corrupt cache files with Northern Softworks’ Tiger Cache Cleaner. Ultimately, it might just take some old-fashioned trial and error to ferret out the culprit.

6. Use Disk Utility If your program crashes on launch and no “unexpectedly quit” message ever appears, go to /Applications/Utilities and launch Disk Utility. From here, select your startup volume and click on the First Aid tab. Then click on Repair Disk Permissions.

7. Reinstall the Program Still stuck? Reinstall the program, using the Installer utility that came with the program—otherwise, you may not properly install key components of the software, and that in itself could be the cause of a crash.

8. Check Console Logs Launch OS X’s Console utility (/Applications/Utilities). Click on the Logs button in the toolbar. From the list on the left, locate the CrashReporter folders (in your user folder / Library/Logs and in /Library/Logs). In these folders are logs for every application on your Mac that has ever crashed.

Find the log file with the name of your problem program and select it. The output you’ll see here is too technical for most people. But occasionally you’ll find a clue to the cause of the crash—for example, a reference to a problematic plug-in. Look carefully at any section with a header including the word Crashed (such as Thread 2 Crashed). By the way, when you get an “unexpectedly quit” message, if you simply click on the Report button, you’ll immediately get a view of the relevant log file.

9. Reinstall OS X If your sleuthing work has not paid off, it may be time to bring out your OS X Installation DVD and start from scratch. Select the Archive & Install option. If this installs an older version of OS X than you are currently using (such as 10.4.0, when you are now running 10.4.4), use the Software Update preference pane to immediately update to the latest versions of all Apple software.

[ Contributing Editor Ted Landau continues to search for new ways to get into and out of trouble. For more troubleshooting tips, see his book Ted Landau’s Mac OS X Help Line: Tiger Edition (Peachpit Press, 2006). ]

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