Repair Permissions in OS X if you observe any of the following:
Your computer in general seems to be slow.
You cannot edit a Folder or it's contents that you think you should be able to.
You get "permission denied", "access denied", or other errors when installing software.
You can't save a file in a location you were able to before.
To Repair Permissions
Open Disk Utility located in your /Applications/Utilities/ folder.
The main window opens, as in the example above, make sure your hard disk is highlighted and click the First Aid tab.
Click the bottom called Repair Disk Permissions.
This will take some time, a progress bar appears and if any permissions are out of order, you'll see them corrected in the status window.
Once complete you'll see the above screen. If your computer cannot Repair Permissions or gives you some other error in the status dialog box, call the CTS Helpdesk right away to have your computer looked at.