It happens to mine every time I try to do anything with live data. If I am just reading codes or interacting with the vehicle in any other way it’s fine. I’ve tried many of the same things you have and I don’t think it’s on the truck side because it was at a dealership a number of years ago to track down what ended up being a bad ground and they didn’t report any connection issues. If I figure anything out I’ll post back.Mine seems to "lose communications with vehicle" quite a bit, too. Tried various updates/firmwares and it seems to do it randomly no matter. Even trying to go in and test the e-fan relays it will crap out.
Let us know if you figure anything out there.
Can't remember if i tried win7 but current setup is
Windows 10 x64
JRE 8 x32