Install the package 'ntfsprogs' - it's in the Ubuntu repositories. That will install a number of ntfs command line utilities. One of them is ntfsfix. If you run this it might fix the filesystem, but you may also need to run chkdsk from Windows. See 'man ntfsfix': ntfsfix is a utility that fixes some common NTFS problems. ntfsfix is NOT a Linux version of chkdsk. It only repairs some fundamental NTFS inconsistencies, resets the NTFS journal file and schedules an NTFS consistency check for the first boot into Windows. Earn money by inviting-1$ per referral link visit.