Unmount a disk set or disk member using Disk Utility on Mac
You can unmount a disk set or a member disk if you need to repair it or perform other maintenance.
Unmount a disk set
In the Disk Utility app
on your Mac, select the disk set that you want to unmount in the sidebar.Click the Unmount button
in the toolbar or beside the disk set name.
After unmounting a disk set, you can disconnect the disk members of the set from your computer.
Unmount a disk member of a set
In the Disk Utility app
on your Mac, select the disk set that you want to unmount in the sidebar.Click the Unmount button
in the toolbar or beside the disk set name.Disconnect the disk member that you want to unmount.
When you create a disk set, you can select Automatically rebuild. Later, when you unmount and disconnect a disk, and then reconnect the disk later, Disk Utility rebuilds the disk member automatically. If you need to rebuild the disk manually, see Repair a disk in a mirrored disk set.