- #Unmount disk failed on older macbook pro mac os
- #Unmount disk failed on older macbook pro full size
- #Unmount disk failed on older macbook pro update
- #Unmount disk failed on older macbook pro pro
Then to unmount it: $ sudo diskutil unmountDisk /dev/disk1įorced unmount of disk failed at least one volume could not be unmounted The Fix On my machine the 4TB WD Elements was /dev/disk1. 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. 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.
#Unmount disk failed on older macbook pro 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. I hope my explanation is useful to someone with the same problem.A tale of a brand new disk drive, a 2TB backup, a disk failure and finally a recovery… Thank you all very much! Your comments were really helpful. So I assume that if you boot from this recovery partition on the drive, it cannot do this part, and the process fails. I think the error "couldnt unmount disk" was due to the fact that somewhere in the process it said it was trying to "relocate the recovery partition".
#Unmount disk failed on older macbook pro full size
This would let the errors be repaired, but still I would get the error " Disk Erase failed with the error: couldn't unmount disk" when I was trying to resize the partition to include the unallocated space.Ģ) So Finally, when booting from the recovery USB stick, and using Disk Utility, I was able to resize the main partition to the full size of the hard drive.
#Unmount disk failed on older macbook pro mac os
It had also created errors on my main Mac volume (when scanning with Disk Utility).ġ) The Disk Utility inside Mac OS was not able to repair the volume, so I had to boot from the recovery partition (cmd + r during boot), and then repair them. The bootcamp assistant had failed halfway through the process, and it could not extend the partition to include the unallocated space ("partition failed").
#Unmount disk failed on older macbook pro pro
I had removed bootcamp and the associated partition from my Macbook Pro running Mountain Lion, and I wanted to reallocate that space on the hard drive to my main Mac partition. I had a similar problem as the thread starter, and was able to fix it by making a bootable Mountain Lion Recovery Volume on a USB stick, as Courcoul suggested above ( ).