Unable to unmount drives due to “Drive is busy status” ?

just run

look if you have any open workspace on the drive location
then run

fuser -k? /path/where/the/drive/is/mounted
or

fuser -k? /device (for ex. fuser -k /dev/cdrom)

then proceed as normal umounting procedure

This is usefull for CDroms which are sometimes stuck on some job and fail to unmount