Thumb drives used to work. I know they did as I have saved programming and watched it via my thumb drive in the past. It would only play via your hopper. Does not work on computers. It served as a bakup for your programming, and help you clear up space on your dvr. I haven't done it in a while but have tried recently and does not work any longer. I believe they have changed the software in order to force you to use their external hard drive that dish sells. Just my guess.
Thumb drives are not compatible with DISH receivers for external storage. Compatible external hard drives must:
1. Meet capacity requirements for your receiver. (Connected to Hopper: minimum 320 GB/maximum 2 TB. Connected to Wally: minimum 500 GB/maximum 2 TB. Connected to other receivers: minimum 50 GB/maximum 2 TB)
2. Have their own power supply.
3. Have a USB 2.0-compatible cable.
4. Not use flash memory and should only be a single-hard disk drive.