I wanted to delete my old time machine backup from my western digital mybook world
i didnt need it for anything, as I have a backup of it :D
i found two ways to do it.
method 1 – ssh.
if you have ssh enabled on your mybook world then you can
open terminal > ssh to your mybook
rm -rf /DataVolume/.timemachine
chmod 777 /DataVolume/.timemachine