I have a WD "my Passport" external HD that is currently formatted for a PC and I would like to format it to eXFAT. Every time I hit "erase" in disk util it just comes up with the error "couldn't unmount disk". Btw, I am running on Maverick. Can anyone help me with this please?
I had the same problem with the same drive. I finally got it to work by rebooting from the recovery partition and formatting it using the disk utility option.
It's proper for the operating system to not unmount a volume if there is, on the volume, an open file that can not be closed.
- note the comment about use of sudo
There's another comparable app but at the moment I can't recall its name.