NTFS file system read-only by Ubuntu
The reason is if you “shutdown” does not actually shut down most of the time in Windows, but only hibernates.
Unmount the Ntfs partition by running
sudo umount -a
to get the partition to mount with full read/write access
sudo ntfsfix /dev/sdaxx #(for example /dev/sda3)
References
https://superuser.com/questions/1394263/ntfs-file-system-read-only-by-ubuntu-remount-doesnt-work