Sometimes Photoshop can exhibit odd/erratic behaviour. This behaviour can sometimes be overcome by removing the Photoshop Preference file. The procedures outlined below is the most common methods of removing the preferences file. This works for Photoshop 6x and newer! Hold down Alt, Ctrl, and Shift keys (Mac: Command, Option, Shift) while starting Photoshop. A dialog box will appear asking if you wish to delete the preferences file. No need to search through your system folders to find it.