Removed Dock items keep reappearing

Sometimes Dock customizations may get reverted either to previous states or to the default set of applications and utilities that are presented when you first create an account in OS X. For the most part, problems with the dock have been associated with one of the following:

1. Problematic Dock database and preferences file
   Removing the "com.apple.dock.db" and "com.apple.dock.plist" files from your /username/Library/Preferences/ folder will reset the dock for your account. Keep in mind that doing this will reset your Dock to the default items, behavior, and location, and you will have to customize it again.


2. Problematic Dock cache
   Using OnyX, Cocktail, or another cleaner application to clear OS X's cache files for the dock (and other system caches) can help in some instances.


3. Problems with MobileMe syncing dock contents
   Resetting the sync data between computers and that on the MobileMe "cloud" can prevent changes in your dock's settings from being reverted by stubborn sync data. We have covered how to reset the sync data in previous articles.

Beyond these account-specific problems and fixes with the Dock application alone, if a program is launched at startup, it will appear in the dock if it is packaged to do so (any program can be altered to not show up in the dock), so checking login items for your account in the "Accounts" system preferences may fix the problem in some cases.

Despite the availability of these common fixes for Dock problems, one Apple discussion poster "Robby Berman", had a very similar problem with Dock items reappearing, but the problem persisted even though he performed these three fixes.

"Hi, I don't use Time Machine (I'm a SuperDuper guy), and I don't need to frequently open my Documents folder, so I've removed both of those icons from my Dock. The last week or so, however, when I reboot in the morning, those icons keep coming back onto the Dock. I've cleaned my Dock cache with Cocktail, tossed the Dock prefs (which annoyingly also tossed my Spaces prefs?) and the Dock db file."

After troubleshooting the situation by testing out various plist files, Mr. Berman found that in addition to the dock's database and account-specific preference files, a global preference file for the Dock seemed to be interfering with the Dock's regular functionality.

This file is called "com.apple.dockfixup.plist" and upon inspection appears to be a structure for setting up the dock for each account by adding and removing some default applications and folder locations. In Mr. Berman's case, this preference file was being used to ensure the Dock was containing certain items even though he removed them, suggesting some corruption in this preference file was causing it to be used at every log in.

Removing this file cleared the problem, which may be acceptable for most people; however, if you have this problem and wish to retain the plist for other accounts, try replacing it by removing the current plist, and then copying a healthy version of its contents (listed below) to a plain text file (not rich text, if you're using TextEdit) and save it with the name "com.apple.dockfixup.plist" in the global /Macintosh HD/Library/Preferences/ folder:

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