Now that we know the destination drive is in good shape, let's make sure that the source drive, your startup disk, has no disk permission problems. Permission problems can prevent necessary files from being copied, or propagate bad file permissions to the backup, so this is a good time to perform this routine maintenance chore.
Repair Disk Permissions
- Select the startup disk from the device list in Disk Utility.
- Select the 'First Aid' tab in Disk Utility.
- Click the 'Repair Disk Permissions' button.
The permissions repair process will begin. The process can take a few minutes, so be patient. When it's finished, you'll see a "Permissions repair complete" message.