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.
Thanks guys….I was having a problem with all my new documents defaulting to Grayscale. This helped me reset it! You ROCK!
Thanks for this simple yet very useful tip! Saved my day!