Drive space reduction

[Sparrow91]

Hello! I just managed to fix the issue which caused my external drive to disconnect and reconnect (by disabling usb selective suspend settings).
Thing is, every time I run a disk check on the drive it stops part way, and the remaining space is reduced!
I had around 20 gb, and now am down to 13 (I tried running chkdsk from command prompt as well, but that didn't work either, it says:

Snapshot was deleted. Chkdsk cannot continue. A snapshot error occurred while scanning this drive etc.?).

Any help would be greatly appreciated!
Many thanks.

 

[hang-the-9]

Could be a bad drive. I would backup your files from it, then try deleting the existing partition, create a new one, and see if that allows it to work normally. If you still see errors, you can try a different cable or enclosure. It may also be a power issue if you are not using a power adapter with it, maybe the USB ports are not providing enough power to keep the drive running.