Repairing disk permissions can help solve various software issues, including certain errors encountered during software installation. If you're not sure whether you should repair your Disk Permissions, search the Knowledge Base for any error messages you're encountering to see if Repairing Permissions is a recommended troubleshooting step.

To Repair Disk Permissions in OS X:

1) Save your work and close all open applications.

2) Go to MacHD > Applications > Utilities and double-click on "Disk Utility."

3) Single-click on your MacHD in the column on the left-hand side of the Disk Utility window. The drive should be highlighted to show that it is selected.

4) Click the "Repair Permissions" button (located near the bottom of the window).

5) When the repair is complete, restart your computer.