A little off topic but may be related. I also lost my tail #. I have to manually add for every flight or it reverts back to default. I wonder if Windows security added some kind of write protection that wont the the sim save our changes. That might explain why its not happening to everyone based on their security settings. May also be why Asobo isnt addressing these issues. I dont even know where to look in Windows settings for this. Just a thought of a common denominator for some issues.