If you find applications are crashing, not starting properly, or acting strangely, permissions may be the problem. File permissions tell applications what can and can't be done with programs and other files. If a file permission gets changed to the wrong value, it can result in crashes and other strange behavior.
Repairing permissions can often fix these problems. However, this function is no longer needed in macOS 10.11 or higher as it is managed automatically by the operating system, and so is no longer displayed in CCleaner for Mac when running on these versions of macOS.
It's also a good idea to repair permissions before and after performing an OS upgrade.
To repair permissions using CCleaner for Mac:
- In the left-hand pane, click Tools, and then click Repair Permissions
- Select the volume you want to repair.
- Click Verify Disk Permissions. CCleaner will display a list of mismatched permissions.
- Click Repair Disk Permissions. The permissions will be repaired.