The disk contains an unclean file system (0, 0).The file system wasn't safely closed on Windows. Fixing.
sudo ntfsfix /dev/sda3
mount -o rw /dev/sda3 /media/XXXX
Mount is denied because the NTFS volume is already exclusively opened.The volume may be already mounted, or another software may use it whichcould be identifiedfor example by the helpof the 'fuser' command.