When I plug my 770 into my Ubuntu pc to put music on it it transfers very slow and then unmounts on its own! The pc then tells me not to unplug my drive without unmounting first because it can damage it even though its still plugged in. Sometimes my card becomes corrupted after that and I have to format it.

Any ideas whats wrong?

tried it with a card reader and it will randomly stop transferring songs halfway through and never finish.