This question already has an answer here:
Mounting external HD Seagate 4 TB in Kubuntu failed with error message:
Error mounting /dev/sda1 at /media/fritz/Seagate Backup Plus Drive: Command-line `mount -t "ntfs" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000" "/dev/sda1" "/media/fritz/Seagate Backup Plus Drive"' exited with non-zero exit status 14: The disk contains an unclean file system (0, 0). Metadata kept in Windows cache, refused to mount. Failed to mount '/dev/sda1': Operation not permitted The NTFS partition is in an unsafe state. Please resume and shutdown Windows fully (no hibernation or fast restarting), or mount the volume read-only with the 'ro' mount option.
However, mounting with Windows 8.1 was OK.
How can I mount with kubuntu again ?