one volume could not be unmounted mac terminal diskutil

You may see a message like the one above, telling you that there may be a program using that volume. The easiest and safest way to force a volume to eject is to open a new Finder window, locate the drive or volume in the left-hand column, right-click or option-click the volume, and select Eject “” in the drop down menu. Sometimes this is because a program is using a file on the volume in question, but other times the volume just seems to be stuck! Fortunately, there’s an easy solution! We’ll show you two ways to force your Mac to let go! Method 1 Unplugging the USB cable and reattaching it then starts the whole process as before!Īny assistance would be most welcome! I can't find an exactly equivalent case on the forum here, hence posing the new question here now.Sometimes OS X doesn’t want to let you eject a volume or an external drive. diskutil list then does not show /dev/disk1 Nothing happens for about 2 minutes, then the Terminal prompt reappears. There is a post with a roughly similar issue here. Gives: Could not find disk for /dev/disk1 But then repeating: diskutil eraseDisk HFS+ DiskName /dev/disk1 Gets: Forced unmount of disk1 failed: at least one volume could not be unmountedīut then despite that error, the disk has been unmounted - it does not appear in diskutil list. So then: sudo diskutil unmountDisk force /dev/disk1 Or this: diskutil eraseDisk HFS+ DiskName /dev/disk1 Trying this: diskutil eraseDisk ExFAT DiskName /dev/disk1 Since then the disk will now no longer show in Disk Utility, but will show in Terminal, like this: /dev/disk1 (external, physical): I first tried to erase the disk in Disk Utility (HFS+, GUID Partition Map), and got an error, saying could not write to last block. It is connected externally via a USB to SATA cable - I have tried two different USB to SATA cables that both work with other drives. I have a 2Tb 2.5' hard disk that was formatted for a PC (but had errors), and have now connected it to my Mac.

One volume could not be unmounted mac terminal diskutil