What to do when Linux is unable to mount my external hard-disk

Still, if you are unable to fix the problem, ntfsfix might help fix the partition. The ntfs-3g package contains the ntfsfix utility (which usually comes preinstalled). If not, you can install it using:

sudo apt install ntfs-3g

Then try to fix the partition by running the following command:

sudo ntfsfix -b -d /dev/sdxx

The -b flag tries to fix bad clusters and -d to fix dirty states. In the above command you have to change the sdxx partition based on your system.

In your particular case, the 634 GB Volume is /dev/sdb1 as displayed in the screenshot you provided, so the command you should run is:

sudo ntfsfix -b -d /dev/sdb1

https://askubuntu.com/questions/1518719/unable-to-access-external-drive-24-4

 #neverforget