I initially had some similar trouble with my 828es.
You might consider the following if not already tried.
- Check Device Manager - Audio inputs and outputs.
- In my case I had trouble with the USB controller. Try different USB3 ports and also make sure no other device is running on the same port.
My Firmware version is 1.3.5+181
Driver Version Windows 4.0.8.2000
For what its worth MOTU Support were very good and eventually we resolved the problem.
Good luck