Hello and welcome to my User Tip
Sometimes you have a problem with System Preferences or something related to it, like it remembering your screensaver or desktop selection, or perhaps it won't launch or launches funky.
This procedure is for deleting the "preferences" file(s) that is located in your (hidden) User/Library folder that can resolve issues like this.
When the computer is rebooted and the associated program launched again, it recreates this file, but blank of preferences, thus since it's rebuilt it's free of problems.
This procedure also works for other programs like iPhoto or iTunes, or whatever that stores a preference file (.plist) in the (hidden) User/Library folder, the procedure is the same, just sub out the program your having problems with .plist file instead of the System Preference .plist file below.
Known preference files issues:
com.apple.systempreferences.plist (corrupted/not launching System Preferences)
com.apple.desktop.plist (corrupted/not working desktop picture changes)
com.apple.safari.plist (safari issues)
See the Steps #12 and #13 for OnyX and it's preference file checker to find other corrupted preference (.plist) files that might be causing your issues.
So we are going to delete a preference file in a hidden folder, this will only affect the preference file, not your personal files or programs.
1: Go to the Finder and select Go menu and Go To Folder
2: Now paste or type
3: Press GO! and a folder will appear
4: Scroll down and find
com.apple.systempreferences.plist com.apple.desktop.plist (or whatever program your having problems with)
5: There may be two of the same named file, drag the one you can to the Trash can
6: Restart the computer and open System Preferences (or problem program) and reset all your preferences again