Disk ejected but still show up in Disk Utility?
Solution 1:
Weird as it is, this seems to be the solution:
- Remove the disk from Time Machine's list of backup destination drives.
- Remove file
tmbootpicker.efifrom the drive's root directory. - Remove file
/var/db/volinfo.database - After restarting and able to mount the drive again, re-add the drive to Time Machine.
Ejecting the drive seems to work now — it finally disappears from Disk Utility's list after the USB cable is unplugged.