Replaced a PCM on a vehicle that I previously tuned. Went to re-tune it, knowing I would need 2 credits. Got the 2 credits, read the vehicle, did my changes, and when I went to load the tune, it said unlicensed vehicle without giving me the option to license. Literally went to the write screen, no license prompt. Renamed the license.dat file, restarted editor, and the write button was grayed out when I opened the file up. Re-read the vehicle again, made changes again, and all was good. Wrote fine.

Should I be reading a previously tuned vehicle with new pcm vehicle after I delete/rename license.dat? Not sure why that should matter.

Any takers?