Hi @formant, sorry to hear about your issues… is restarting or reinstallation providing any solution or are you unable to connect to the device?
This being the case, it would be worth raising a ticket with Tobii Tech support directly @ https://help.tobii.com/hc/en-us/requests/new who may be able to make further diagnoses upon receipt of diagnostic log data.
I assume you have the latest Tobii Core Interaction Software installed also?