macOS
Why can’t First Aid check a disk?
Q After Time Machine made its first backup of my M1 iMac, I ran Disk Utility’s First Aid, but it couldn’t check the backup disk as it couldn’t unmount it. How can I check that backup is good?
by ANDY INNES
A The simplest way to check special volumes such as Time Machine backups is to start up in Recovery, select Options, and use Disk Utility from its main window. That ensures that other processes, Time Machine or Spotlight indexing, won’t access the volume, enabling Disk Utility to unmount it cleanly.
