Mine

:~$ sudo  ntfs-3g /dev/hdb /mnt/windows_H
Error opening partition device: Device or resource busy
Failed to startup volume: Device or resource busy
Failed to mount '/dev/hdb': Device or resource busy
Mount is denied because the NTFS volume is already exclusively opened.
The volume may be already mounted, or another software may use it which
could be identified for example by the help of the 'fuser' command.