Burn jobs halts before finishing Alarm:0

Lightburn halts prematurely and is throwing an Alarm:0. I cant find any information on this Alarm code. It has happened to the last half dozen attempts. This is the console log snipet.
Starting stream

Layer C00

ALARM:0

On or near line 367923:

Job halted

Stream completed in 25:29

Can anyone point me in the direction of where I should look? I thought it might be windows USB going to sleep, but i have disabled that and restarted. In the list of published codes, there doesn’t appear to be a Alarm:0 code (just my luck).

any help would be greatly appreciated.
Jason