Comment 18 for bug 85424

I still get this problem in Gutsy after a suspend/resume cycle.

It appears that if the drives mount as a different device after resume (which can happen if you have more than one USB drive attached), /media/.hal-mtab contains two entries for the same drive after the resume. Eg if a drive used to be /dev/sdf1 and after resume it is /dev/sdg1, both entries then appear are in .hal-mtab, and if you try to to unmount the drive, it complains it can't remove the directory, and neither entry in .hal-mtab is deleted.

If there were already two entries in the file when you resume and the drive mounts as a different device again, you get three entries, etc.

This 'cannot unmount drive' behaviour persists indefinitely until you manually delete .hal-mtab. If you then suspend/resume it can reappear.