How to best troubleshoot problematic Mac applications

Erik Eckel offers his tried-and-true tips for narrowing down problems with Mac applications and how to troubleshoot them.

Application failures prove troublesome and time-consuming for technology professionals at small and medium businesses, but they're even more problematic for enterprise administrators. Apple, as part of its training for the Apple Certified Support Professional certification, advocates an eight-step process to addressing application errors. By following these steps, enterprise support professionals can add efficiency to troubleshooting efforts.

Restart the application

It sounds too simple and obvious to be true, but I've lost count of the number of application errors I've seen fixed by simply rebooting a problematic system or restarting a failing application. When restarting an application, you may need to kill hung processes using Activity Monitor, but restarting an application often solves myriad issues.

Try another known working file

When an application hangs or crashes opening a specific file, try opening a different known-good file using the same application. If you can open a different file using the same application, you can have confidence that the file opened earlier is causing the trouble. In such cases, you can try opening a backed up (uncorrupted) copy of the original file. If the second file cannot be opened, then it's likely the application is causing the issue and troubleshooting can continue.

Try another application

If an application hangs when opening a specific file, whether a document, spreadsheet, database, image or other file, try opening the file using a different application. For example, if a .JPG won't open using Preview or a document won't open using Microsoft Word, try opening those same files using Adobe Photoshop or Pages. If the file opens using the secondary application, it's likely the trouble lies within the original application. When the file opens using the second application, you can try making a fresh Save using the alternative application and then open that newly saved file using the original application. If a second application can't open the file, however, it's likely the file itself is corrupt and to blame, in which case you'd want, again, to recover from a backup.

Try another user account

When an application crashes regardless of the file that's opened, try logging in and opening the file as a different user. If the application works properly within a different user account, it's possible a user-specific resource is causing a conflict. When such cases arise, search for corrupted caches, preferences, and resource files within the original user's Library folder.

Check diagnostic reports and log files

While most applications don't keep their own log files, Mac OS X creates a diagnostic report whenever an application crashes. Problem reports are logged within the user's ~/Library/Logs/DiagnosticsReports folder as applicationname.crash. When a program hangs, a similar report is logged within the /Library/Logs/DiagnosticsReport folder using the file format applicationame.hang. View these reports by opening Console and clicking the Show Log List button. Log files are displayed within the Diagnostic Information section.

Delete cache files

Applications, over time, create cache files to speed performance. Occasionally these caches become corrupt. By clearing them out, you can often eliminate application errors. Look for problematic cache entries within the /Library/Caches and ~/Library/Caches folders. Deleting a problematic application's cache often eliminates issues that were preventing proper operation.

Replace preference files

Preference files--which record such information as serial numbers, license keys and similar information-are constantly writing and rewriting preference updates to the application's configuration property list file. These files are stored within the /Library/Preferences folder. When troubleshooting a failing application, administrators can rename a suspected bad property list file. The application will write a new one, using default values, upon restarting.

Replace application resources

If application errors occur only within a single user account, the trouble is likely due to a corrupted resource within the user's home Library folder. You can narrow your troubleshooting efforts by focusing on corrupted resources within the user's Library folder if this is the case. If application errors occur using multiple user accounts, however, uninstall and reinstall the application. Doing so, potentially corrupted files will be replaced, and reinstalling may provide an opportunity to load a new version of the software that includes bug fixes designed to address the very issues that caused the original trouble.

If reinstallation fails, it's possible a shared resource (such as fonts and keychains) is causing the corruption. Review the error logs for a potential culprit and move any suspected offender temporarily out of the Library folder for testing. If those steps fail, and especially if other corruption is present, there may be a larger system-wide file storage or hardware error. Ensure you have a verified backup and then confirm file and disk operations are completing properly.


Erik Eckel owns and operates two technology companies. As a managing partner with Louisville Geek, he works daily as an IT consultant to assist small businesses in overcoming technology challenges and maximizing IT investments. He is also president o...