Mac OS X: How to troubleshoot a software issue

Learn ways to identify and troubleshoot software issues.

Is it a software or hardware issue?

You may not be able to determine this with certainty until you troubleshoot. Troubleshoot software before hardware unless the issue prevents any software troubleshooting. See Isolating issues in Mac OS X for more information.

Where does the issue occur?

If the issue occurs in one application only

For example, one application does not open or unexpectedly quits. Mac OS X v10.4 and later can help with applications that unexpectedly quit by offering to open the application with default settings. If this doesn't help, skip to "Drag the application to the Trash and reinstall it if the issue persists..." below.

  1. Make sure you are using the latest version of the software. Check with the manufacturer if the product is published by a third party.
  2. If the issue only occurs while using a specific document, try creating a new document or replacing your document with a backup. Your document may be damaged. If possible, try testing with either a new file or a known-good file.
  3. Drag the application to the Trash and reinstall it if the issue persists. Some Apple applications that may have been included with your computer can be reinstalled by using the Install, Restore, or iLife disc that came with the computer. See these links for more information:

If the issue occurs in various applications, or in Mac OS X

For example, if no applications can be opened.

Tip: If the issue began right after you performed a Mac OS X re-installation (excluding erase-installation), see Applications don't work after reinstalling Mac OS X.

  1. The first and easiest test to try is to see if the issue affects a different user account on your Mac. Each user account has customized preferences and other items stored in its home directory. You'll first need to create an additional user if one does not already exist (follow steps a-h below). Then, log out of the current user and test the issue in the new user account.

    If this resolves the issue, there may be an issue with a file in the home directory of the original user account.

    1. From the Apple menu, choose System Preferences.
    2. From the View menu, choose Accounts (or choose Users if using Mac OS X v10.2 or earlier).
    3. Click "+" (or click New User if using Mac OS X v10.2 or earlier).
    4. Give the new user a name and short name.
    5. Mac OS X v10.3 or earlier only: Click the Password tab, and give the user a password.
    6. Mac OS X v10.3 or earlier only: Click Security.
    7. Select the checkbox for "Allow user to administer this computer". This makes the user account an administrator.
    8. Click OK, or quit System Preferences.
  2. Start up in Safe Mode (Mac OS X v10.2 or later only). If the issue does not occur, there may be an issue with a startup item, login item, or kext file. Refer to this article for troubleshooting suggestions.
  3. If the issue does not appear to be related to preferences, a login item, or a kext file, and still persists in Safe Mode, there may be an issue with a cache file in your home folder:
    1. From the Finder's Go menu, choose Home.
    2. Open the Library folder.
    3. Drag the Caches folder to the desktop.
    4. Attempt to reproduce the issue.
    5. If issue is resolved, drag the Caches folder to the Trash.
    6. If issue persists, from the Finder's Go menu, choose Go To Folder.
    7. Go to this folder: /Library
    8. Drag the Caches folder to the desktop.
    9. Attempt to reproduce the issue.
    10. If issue is resolved, drag the Caches folder to the Trash.
    11. If issue persists, go to step 4.
  4. If the issue persists, there may be an issue with a third-party font file in your home folder.  See this article for information about using Font Book to enable or disable fonts in Mac OS X v10.3 or later.

    Disabling fonts in Mac OS X v10.2 or earlier

    1. From the Finder's Go menu, choose Home.
    2. Open the Library folder.
    3. Drag the Fonts folder to the desktop.
    4. Log out and back in, or restart.
    5. Attempt to reproduce the issue.
    6. If issue no longer occurs, reinstall any third-party fonts. Delete the former Fonts folder when finished, then stop here.
    7. If issue persists, from the Finder's Go menu, choose Go To Folder.
    8. Go to this folder: /Library
    9. Drag the Fonts folder to the desktop.
    10. Log out and back in, or restart.
    11. Attempt to reproduce the issue.
    12. If issue no longer occurs, reinstall any third-party fonts. Delete the former Fonts folder when finished.

Learn more

If the issue persists

Perform other troubleshooting steps listed in this article.

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