At first, I was trying to transfer with the prime plugged into my keyboard dock with USB debugging enabled. Then I disabled USB debugging. Then I tried, with debugging disabled, when connecting to the tablet directly. Finally I tried connected directly to the tablet, but with USB debugging enabled.
At every step in the process I will get through one folder or so, and then get an error on my desktop that says the device has stopped responding or has disconnected, and the transfer will fail.
With a bit more trial and error it seems to be that any time I interact with the prime in any way while it is transferring (even something as simple as scrolling back and forth a little on the home screen to keep it from going to sleep) it fails.
I'm not rooted, I'm on the standard firmware (.21 - latest as of now), and I've tried restarting the prime.
I can not make these files transfer and it's driving me insane. Anyone have any suggestions or theories on how to fix this?