Can't do any modifications on NTFS disks

Ubuntu will mount ntfs file partitions as read only if they are not clean, i.e., if the file system is not in a consistent state.

ntfs is a proprietary file system. Therefore, ntfs file systems should best be checked on a Windows system. Although Linux has the ntfsfix tool, it allows for relatively basic repairs only.

If you do not anymore have Windows, then it is strongly recommended to reformat the drives to ext4 or another file system that is fully supported under linux. Keep ntfs around only if you intend to use it sometimes with Windows or for non critical uses (e.g. a TV that only reads ntfs format, if the file system is broken, you just reformat).