I have the Ultimate Edition and every time I try to launch the game it tells me there’s an update, but ends up telling me “There was a problem with the update.” I’ve done multiple power cycles/restarts to no avail. I even spent nearly 2 hours with Xbox support yesterday, and they couldn’t even help. I’ve download other updates lately with no issue as well, so I have no idea what to do. Hopefully someone here can help me out. I have the Preview Dashboard if that means anything too. 
If you’re running the BETA software, you should consult the latest Known Issues list, which includes:
“Forza 6: Forza 6 may fail to update due to an installation stopped error.”
Report the problem (let the console sit for at least three minutes so a report is automatically sent to the Beat Team) in the proper Beta forum. It is NOT a game issue, but a problem caused by the beta software. Whenever you’re running beta software, first check the beta information before attempting to get a fix elsewhere.
Thank you. I’ve had the Dashboard for at least a week and it still tells me “Group Not Found.” Now I’ve gotta get that all straightened out, ugh.