I have seen some times my external drives to fail to mount correctly on Ubuntu giving the message:
“$LogFile indicates unclean shutdown (0, 0)
Failed to mount ‘/dev/disk/by-uuid/FE5C75355C74E9B3’: Operation not supported
Mount is denied because NTFS is marked to be in use … ”
This is frustrating and scary at first. But finally it seems to be a common problem when somebody does not “remove safely” the drive, so the NTFS log of the drive thinks it is still on.
Fortunatelly there is a very easy to use tool:
$sudo ntfsfix /dev/drive_name
where /dev/drive_name can be found by the command: (sudo) fdisk -i.
Many many thanks to this post!