I find if I have NTFS problems, throw it back on windows, do a disk repair then come back to Linux.

Also remember to fully shut down (not sleep or hibernate) windows before removing the disk so windows doesn't lock up anything

Edit: the error actually tells you the latter of what I mentioned... So back to windows you go for a shutdown before removal

Did you perform a full shutdown of Windows (Windows doesn't fully release the partition on a normal shutdown)?

@Dust0741 @linux also you should disable fast boot in windows which is similar to hibernate and cause this issue.

@Dust0741 sometimes this can help -> in a linux console: ntfsfix -b -d /dev/sda1 oder ntfsfix -b -d /dev/sda2.

If you really need the data on it, get another disk and make an image of the failed drive asap.

If not, skip that step.

See if testdisk can detect your partitions and read data from them.

If you can access it on Windows, that's a good thing and all you need is a disk repair there. If you cannot access it even on Windows, you'll need file recovery (and another 4TB disk).

However, note that there is a good chance for NTFS disks to get corrupted on Linux if you unmount them without getting the notification that indicates it's safe to remove the disk.

So I really recommend you to find a temporary disk (or buy a new one) and copy everything to it and format your disk as a Linux file system of your choice and move your files to it, before you get a real headache with NTFS (talking out of experience).

Also note that, it's possible for NTFS disks become inaccessible if fastboot option is enabled for Windows on BIOS, if so disable it.

Read the error and do what it says? Lol