If you have problems with a disk or volume, use Disk Utility to test and repair it. You can also verify and repair permissions on a Mac OS X startup disk. Occasionally the user permissions associated with files or applications become damaged, which can prevent a file or application from opening.

To learn more about testing and repairing disks, open Disk Utility, in the /Applications/Utilities folder, and choose Help > Disk Utility Help.

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