Applications will not unhide

We previously reported an issue in which applications will not minimize. There seems to be a similar problem affecting some users, in which applications that have been hidden will not unhide, and remain so until they are force-quit by the user.

Apple Discussions poster Aquanaut:

"I have had a regular problem since Tiger (and maybe earlier) where a hidden application cannot be brought back using 'show.' Everything looks okay but clicking the icon in the dock or using any other methods for App selection doesn't work...I've tried everything from deleting the dock prefs to running Disk Warrior, fixing permissions, etc. The only solution when it happens is to force quit the app."

We suspect that this problem is caused by some applications more than others, but users have not been able to pinpoint an exact culprit, and the problem does occur at seemingly random times for the affected applications. This problem has affected users for a long time, since Tiger for some, and for others since installing Leopard.

Potential Fixes and Workarounds:

Restart the dock

There are no known fixes to preventing this problem from occurring, though it is possible it may have to do with the Dock, which holds responsibility for much of how applications behave in OS X. Users can try restarting the Dock to see if that helps the situation with the problematic application. To do this, open the Terminal and type the following command:

• killall Dock

This command will close the Dock, and the application will be restarted automatically. It may also be necessary to reset the Dock's preferences by removing the preferences files from the ~/Library/Preferences/ folder. The files to remove are: "com.apple.Dock.plist", and "com.apple.Dock.db". By removing these files, the Dock's behavior and applications will be reset to the default, so it is recommended to create a list of the Dock's applications before removing these preference files.

Force-quit the affected applications For some users, this problem happens with the Finder, and luckily with this application users can easily restart it without losing data. For other applications, however, force quitting may result in loss of work or settings, depending on the application. Still, to force-quit applications or relaunch the Finder, by pressing the opt-cmd-esc key sequence and selecting the problematic application from the list will allow the program to be restarted so it stays in the foreground.

Troubleshoot with a new account Users might try creating a new account to see if the problem still persists there. If so, then it indicates something installed in the User's library folder is the culprit, and further investigation can target this folder. In addition, users may wish to just migrate to the new account if it is problem free, which may be easier than pinpointing specific problems. There are ways to change the new account to have the same name as the previous account, so if a new account fixes the problem users can alter it to have the same login and password as the previous one. This process is outlined in this MacWorld article. An alternate to this process is to delete the previous problematic account (preserving user data) and recreate one with the same username and password, then test the new account and migrate data over to it if there are no problems.

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