I have the same problem with my Xtool D1. it starts then almost immediately stops with one file. why I do not know. life is not nice. 
I’m going to move this into the xTool channel.
My suspicion is the firmware version.
When your xTool connects to LightBurn there should be some information about the firmware version in the Console window. If you copy and paste it I can see if it’s one of the likely candidates for success.
I same thing well almost, (I have Xtool D1) it starts then almost immediately stops
I’ve moved this post to your own thread in the xTool d1 section so we can start looking at a more likely line of reasoning.
I think you’re having the same firmware problem that you were having before:
Can we talk one on one?
if you have great info to share leave it here that way in the future some other person with the same issue gets it solved
Are we getting an answer here? I have the same problem. Things were working just fine a few days ago but when I came back to my shop and powered back up I now have this issue. I have a Windows10 computer connected via USB-C to an xTool D1 running the latest firmware (V.40.30.007.01 B4). I am using (well, trying to use!) Lightburn v 1.2.01.
Although I can frame, I have noticed that this fault also occurs doing a simple “home” click.
The behavior is though the laser cycles power. I get no faults in the system or application logs and the console does not record any error other than a lost/restored connection.