- #Mac os volume could not be unmounted update
- #Mac os volume could not be unmounted full
- #Mac os volume could not be unmounted mac
Next step then was to force it to unmount from the command line. Unfortunately – Erase complained as it couldn’t unmount the disk in the first instance – just giving a ‘Couldn’t unmount disk’ message. I don’t mind losing the data – I just want a working drive back… Couldn’t Unmount Disk I tried a Verify, and then a Repair – which initially looked promising as it found a problem… but then it said it couldn’t repair and I should consider reformatting. Success! I could at least see the drive in Disk Utility now.
#Mac os volume could not be unmounted mac
The next thing I tried was plugging the drive into an older Mac Book Air I have (which was running an older version of macOS). A bit more digging revealed the drive could be seen in System Report (via Apple logo on menu. The drive was still invisible to Finder and Disk Utilities.
#Mac os volume could not be unmounted update
So the first thing I did was update the OS (to High Sierra – as it turns out – a pretty substantial upgrade). A quick google revealed this wasn’t uncommon, and a couple of posts mentioned issues with Sierra. Whatever I did – I couldn’t get the new 4TB drive to show. Lights were on and flashing, but now they were not visible in Finder.Ĭue several attempts and unplugging, replugging, restarting the computer. The connection was flimsy – so I figured they both just lost power and reset. I then plugged another WD Elements (an older 500GB one) into one of the other USB hub ports – and both drives disappeared from Finder. I could see the files on the drive – I even moved a couple of folders successfully on the new drive. When I got back from work it looked like it had finished ok. The 2TB transfer was left overnight and during the day. The MyBook Duo used the official Apple Thunderbolt adapter – which is pretty solid, and the WD Elements was plugged into a 3 port USB hub – which is a bit flimsy. Its a 2017 model so has no native USB or Thunderbolt 2 ports – just USB-C, so I had to use adapters to plug in my drives. I formatted it and started with a 2TB backup of my 4TB (2x2TB RAID1 WD MyBook Duo). I recently bought a 4TB Western Digital Elements external drive in the Black Friday sales to add to add to my backup family. It does not store any personal data.A tale of a brand new disk drive, a 2TB backup, a disk failure and finally a recovery… The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies.
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#Mac os volume could not be unmounted full
Full step by step instructions for this process are available here. Now attempt the task that caused the error again. Once you’ve got your boot drive, run Disk Utility and use the ‘First Aid’ option to verify the disk and repair if needed.