Resetting Photoshop’s Preferences
Here’s a quick way to reset your preferences in Photoshop: Press-and-hold Command-Option-Shift (PC: Ctrl-Alt-Shift) while you start Photoshop. As you start the program you will get a pop-up dialog asking you if you would like to delete the settings file. Deleting the file will create a new set of preferences from scratch.
Good to know. When it happened to me I deletet the file manually, this way is a much faster and better way to do it directly in photoshop.
Thanx for the tip!