I am running Mavericks OX 10.9.1 and am trying to erase an external hard drive that has been partioned. I keep coming up with the error message "Disk Erase failed with the error: Couldn’t unmount disk." Any suggestions?
iMac, OS X Mavericks (10.9.1)
I just came to the same solution! Thanks. Wish I had seen this about an hour ago!
don't partition the physical disk ie the upper name. erase the volume first ie the lower name then parition the physical disk.
This worked for me!
Ejecting the drive & trying to Erase again in Disk Utility worked for formatting my WD Passport for Mac, thanks.
Disk Erase failed with the error: Couldn’t unmount disk. Running Mavericks
