Ubisoft has fixed some of the issues with Avatar, Outlaws and the Windows 11 24H2 update, but the big three Assassin's Creed are still borked

pcgamer.com:

Printers, webcams, routers—the usual things that have issues after a big operating system patch. For the Windows 11 24H2 update, games also joined in with the failure party, specifically five big releases from Ubisoft and the problems were so bad, that Microsoft prevented the update from being applied to any PC with those games installed. Ubisoft has released hotfixes for two of them but Assassin's Creed Origins, Odyssey, and Valhalla are still without a solution.

Microsoft has confirmed that Ubisoft's temporary patches for Avatar: Frontiers of Pandora and Star Wars Outlaws resolve problems with crashes, though you still might experience performance issues. That means if you have either of those games installed (fully patched, of course) then you'll eventually be offered the Windows 11 24H2 update, should you be using that operating system.

However, if you have Assassin's Creed Origins, Odyssey, or Valhalla installed, then Microsoft's big update for Windows will still be unavailable and you're strongly advised not to circumvent the block by installing Windows 11 24H2 directly (e.g. via Microsoft's media creation tool).

The big three AC games all use Ubisoft's proprietary Anvil engine. Avatar and Outlaws, thought, use Snowdrop and while that's also a Ubisoft engine, it's predominantly developed by Massive Entertainment. Microsoft hasn't given any indication as to what's causing the problems with 24H2 and these specific games, but the fact that the Snowdrop-powered ones have been fixed first clearly suggests that it's something fundamental with how the engine interacts with the operating system.

It's such an unusually specific issue, with no other games that I'm aware of having the same problems with Windows 11 24H2 (freezing during loading or gameplay, crashing to desktop, black screens), that this might not be Microsoft's fault at all. Or at the very least, it's not something that its developers have messed up. At the same time, I don't believe that Ubisoft is at