Three times in the first two weeks, I've woken up with the last 3 hours or so of data missing, and the message on the screen "Headband Not Connected - press blue button on the headband." Pressing the blue button doesn't work.
After calling tech support, I was told to press the error message on the screen. This led to a sequence of steps to unpair and re-pair the headband. The missing data appeared.
Just thought I'd put this here in case someone comes by looking for answers.