have you tried repairing disk permissions?
Quit any open applications/programs. Launch Disk Utility. (Applications/Utilities) Select your boot volume (usually called MacintoshHD) in the panel on the left, select the FirstAid tab. Click: Repair Disk Permissions. When it's finished from the Menu Bar, Quit Disk Utility and restart your Mac. If you see a long list of "messages" in the permissions window, it's ok. That can be ignored. As long as you see, "Permissions Repair Complete" when it's finished you're done. Quit Disk Utility and restart your Mac.