My drive occasionally gives a $Mft error.

$Mft errors usually indicate a corrupted partition. This article gives troubleshooting tips.

Unfortunately, $Mft errors usually indicate a corrupted partition.

Please follow these steps:

Troubleshoot the partition.
1. Backup the data on the drive (if it is not already backed up).
2. Once complete, or if the data was already backed up, use chkdsk /f to try to repair the partition.
  Also see Document ID: 184611 for more information.
These errors are also sometimes seen in conjunction with delayed write failures.
Confirm that the external drive you have is supported in the operating system you have. For example, no external drives are supported in Windows 2000 Server, Windows 2003 Server, or Windows 2008 Server. A drive connected to a Server computer like this might indeed work for a while, even a great while. But often problems like the $Mft error occur.
So, use the external drive on a different, supported operating system.
See Document ID: 211931 - Will my drive work with Windows 7?
This error sometimes means that the drive itself is failing.
Use Seatools for Windows or the drive's bundled diagnostic software to test it.