The most useful and immediate solution is to reset the Photoshop preferences file. To do this, on the Windows platform press and hold Alt + Command + Shift (Windows) while on Mac OS press Option + Command + Shift (Mac OS) while starting Photoshop. You are prompted to delete the current settings. New preference files are created the next time you start Photoshop. If the same problems persist when the system restarts, we recommend that you reinstall both Photoshop and the package with our items.