Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Level 1

8 points

Disk Utility cannot unmount disk, despite booting from a different disk.

I'm running a Mac Pro 12 core with Snow Leopard. I have two start up disks, an SSD and a 4 TB SATA. Upon start up with either disk I can do one or two simple things opening a disk, emptying the trash... small things like this) before I get the BBOD... When I try verifying the 4TB disk, I get a couple of errors, and a notice to repair the disk. When I try to repair the disk, it says the disk cannot be unmounted. I've booted from my SSD, but can't get the 4TB to unmount so I can repair it with Disk Utility.

Any suggestions?

MacBook Pro, iOS 6.1.6, 10.6.8 OS

Posted on Mar 14, 2018 8:29 AM

Best reply

Darvadee Author

Level 1

8 points

Posted on Mar 15, 2018 1:22 AM

In case anyone else runs into this, I took the Mac Pro startup disk that was causing problems out of the casing, put it in an external reader, plugged it into my MacBook Pro, and repaired it with disk utility on my laptop. Took about 30 seconds, and now works perfectly.

I wish I had thought of that before spending about 30 hours trying to repair it with the Mac Pro.

View in context

Disk Utility cannot unmount disk, despite booting from a different disk.

Similar questions