Waiting for Main Unit
I just experienced that error message. It was difficult to see on the display as I had the contrast turned down.
I tried everything, checked the fuse, reconnected the remote head, swapped SD cards, different USB cords and different computers.
Finally after all day without the radio I heard the POST beep and it was back on.
No problem with the SD card, still using the same one now.
I kept looking for a reset button to hold down!
I believe the computer unexpectedly turning off with out properly shutting down caused the issue. I was not updating files at the time.
WS1098 Win 7.
It was a devasating experience.