Occasionally in OS X file ownership and permissions get changed by applications and program installers. When ownership and permissions get changed, things just don’t work as they should.
The symptoms might be programs quitting unexpectedly, preferences not being remembered, programs not launching, etc. This is where Repair Disk Permissions utility comes in.
To repair permissions, open the Disk Utility program found in the Applications/Utility folder on your hard drive. At the top of the Disk Utility window is a row of tabs. Click on the First Aid tab. On the left is a list of the disk and volumes mounted on your computer system.
You need to click to highlight your main hard drive. In the right window pane in the lower left click on the repair disk permission. After the repair you can restart your Mac. I would also recommend running this repair after each new software update runs.
