For example, a file from the disk you are trying to erase could be open, which means that you can’t proceed with the erasing unless all the files are closed.Another possible reason is the presence of malware. This can happen during partitioning, disk verification and repair, and even during formatting, and there’s usually little to no additional information provided as to how to resolve the problem or even what the problem is with regards to the error message or the app in Mac OS.This is the recommended method because it should always fix the error. 1. I could see it in Disk Utility (on both OS’s). I read not so great reviews on others, but I’m glad the first one worked.If you connect a damaged disk, and the light indicates heavy activity but the OS does not immediately complain or appear to mount the disk, it is likely running fsck in the background.In my case, I noticed that fsck was going through an error/repair/recheck loop continuously, and not fixing the problem. When this happens, simply follow the solutions listed above and you’ll be good to go. Using the above command can interrupt file read/writes, which can cause file corruption. You can use an installation drive or a recovery drive, as long as it is bootable and it is separate from the primary boot disk where your macOS is installed.Here are the steps you need to follow to resolve this error using a USB boot drive:If the “Couldn’t Unmount Disk” error message appears when doing First Aid on your disk or formatting a non-boot disk, the first solution will not work.

The following discussion allows you to unmout device and partition forcefully using mount or fuser Linux commands.

Open disc utility find my external drive , that will not un mount or partition. Is there a way to at least get the files off of it if it is damaged?diskutil unmount /dev/disk3;diskutil mount /dev/disk3;echo “Remounted Volume”Use the proper syntax to fix your mount and unmount command.My external drive is now greyed out in Disk Utility (though the repair function works and says the disk is OK).

Windows found the correct driver and automatically ejected the problem/stuck DVD. But before you do so, here are some of the basic troubleshooting you should take care of first:Once you’ve completed the steps above, you can now proceed with the main solutions:If “Couldn’t Unmount Disk” error occurs when you are trying to modify the boot drive, the easiest solution is to boot your Mac using another drive, and then run Disk Utility from that disk. I used the command line:To force the unmount of the disk, and now First Aid is proceeding. !The command line approach to mounting and unmounting drives is intended for techies, of course it is complicated. ” hdiutil eject /Volumes/LaCie ” works in terminal but I cant replicate the mount part.This definitely does work, it just takes some time. Disk Utility usually works trouble-free, but a frustrating “Couldn’t Unmount Disk” error can halt whatever the attempted task is right in its tracks. Thanks so much for this.Sorry everyone, I’m a massive noob. Can anyone suggest a way to do this?Thank you so much, mounted my disc and able to copy everything off.Too complicated! 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.. However, after a very long time it would sometimes mount the disk in read-only mode, and tell me that the disk could not be repaired and I should copy files I needed as soon as possible.I found that if I killed the fsck process, it would skip right to mounting it as read-only (which, if you have a damaged disk, is probably the best you can hope for).Note the second column (a number) will be the process ID (e.g.

This is what the results say:What am I doing wrong or what is the issue? Copyright © Software Tested 2013 - 2020 All rights reserved. If you have any queries and problem please comment in comment section. Just in case anyone finds this…Hi MacBook a1181 Mac os X 10.7.5 lion factory reset disk1s3 read write message disk locked how this factory reset possible this modelthank you so mucho, the one that work for me was using the terminalRestarting the computer solves the problem. You saved my HD many times because of this tip alone. Then I typed the command to mount and it did. The grep tip within “diskutil list |grep OSXDaily” enabled me to identify the correct Identifier in the o/p. But what if you want to be able to mount, unmount, and remount drives from the command line?

Worked like a charm and quickly. The last echo portion is optional but it makes the entire command action even more verbose.

Even tried terminal, and force mount on terminal and it’d give me the whole try Read Only mount –also didn’t work.

Your method is the only thing that worked. It seems to unmount a mount my USB3.0 thumb drive also.Thanks! Anyway, worked perfectly. # umount -f /mnt. You can use an installation drive or a recovery drive, as long as it is bootable and it is separate from the primary boot disk where your macOS is installed.Here are the steps you need to follow to resolve this error using a USB boot drive:If the “Couldn’t Unmount Disk” error message appears when doing First Aid on your disk or formatting a non-boot disk, the first solution will not work.

If the light on your hard drive is blinking or you can hear the motor spinning, that means you Mac is trying to read it. I need mount disk1s2. You’ll notice the drive is no longer accessible in Finder, but it will still be visible through diskutil from the command line, or the more familiar Disk Utility app in Mac OS X’s GUI.If you can unmount a drive, of course you can mount or remount one too. In case all these methods fail to repair the disk, you … Disconnect the disk member that you want to unmount. I couldn’t get it to unmount or mount but using both did the trick. Backups didn’t happen, and I looked and found the drive had not mounted.

That’s exactly what we’ll cover here.Let’s first cover unmounting drives. This will Again, if the disk throwing the errors is the same as the primary boot partition that Recovery is also on, the above method may not work to resolve the problem. Volume Erase failed Volume Erase failed with the error: “Couldn’t Unmount Disk”.