External Hard Disk Not Mounting

In Ubuntu....

In some cases external hard disk though visible does not mount and shows the following error...
 

Error mounting: mount exited with exit code 13: $MFTMirr

does not match $MFT (record 0).

Failed to mount '/dev/sdb1': Input/output error NTFS is

either inconsistent, or there is a hardware fault, or it's

 a SoftRAID/FakeRAID hardware.  In the first case run chkdsk /f on Windows

 then reboot into Windows twice. The usage of the /f 

parameter is very important! If the device is a SoftRAID/

FakeRAID then first activate it and mount a different 

device under the /dev/mapper/ directory, (e.g./dev/mapper/

nvidia _eahaabcc1).  Please see the 'dmraid' documentation

for more details.

You can solve this by using ntfsprogs package

In the terminal (Ctrl+Alt+T) type the below following codes

Get package Code:

sudo apt-get install ntfsprogs

fix it Code:

sudo ntfsfix /dev/sdb1 

This should fix the problem without rebooting the PC.

If still the problem persists then you need to plug it into the windows operating system to run checks for a proper fix.