Full PC freeze, no crash report, hard reset needed

Development Platform & Builds
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1

No crash report.

2

Steps to Reproduce
Hey! We’re facing an issue potentially unrelated to Unreal Engine, but it’s always worth to ask the community. I know many other Unreal Engine games are/may be affected.

Our beta players report full PC freeze, no crash report is shown, PC needs to be rebooted. This started with Windows 11 24H2 update, but is much more visible with recent NVidia driver updates (576).

We’re working with players on collecting the information but it is extremely hard to find any useful leads. We are also in sync with NVidia.

Maybe you have some ideas? Existing experience?

Here is what I found so far:

https://www.ubisoft.com/en-gb/game/avatar/frontiers-of-pandora/news-updates/6lnv8kQkS3hHEhcgnV5QRh/avatar-frontiers-of-pandora-title-update-12

[PC] We will deploy a temporary fix for players who were experiencing issues playing on Windows 11 24H2. Please note that you may experience some performance issues while we work on a more permanent fix. As soon as it is ready, we will let you know. Thank you for your understanding.

https://www.ubisoft.com/en-us/game/star-wars/outlaws/news-updates/1sXCR6GmB3Kn7OrKiy8DPO/star-wars-outlaws-title-update-140

Also, we have just deployed a temporary hotfix (v1.4.1) for players who were experiencing issues playing on Windows 11 24H2. Please note that you may experience some performance issues while we work on a more permanent fix. As soon as it is ready, we will let you know. Thank you for your patience.

I don’t know any details, I suspect it might be process affinity or priority.

I also found:

https://www.pathofexile.com/forum/view\-thread/3594471/page/552

Just wanted to let you guys know, Microsoft wrote back to my bug report, that the bug will be fixed with Windows 11 insider version >= 27785. As I always suspected, this issue was indeed a bug in the Windows 11 24h2 CPU scheduler. Here is the official answer by MS:“[…] that the bug you have signaled has been correctly solved, and it was tied to an erroneous approximation of the cycle counter when the frequency of the CPU was going more than 4 GHz, which is the maximum amount representable with a UINT32.Windows Insider versions >= 27785 should solve the problem.”

Thanks id advance!

3

Thanks for reaching out about this. We have not gotten any reports about this kind of crash, and from the description of it, this is likely a bug in the Windows operating system. Have you tried to reproduce this crash locally with the Microsoft Insider patch mentioned in the last comment you mentioned?

4

Hey, we were able to narrow it down. Here is a breakdown of what we found.

  1. Windows 11 24h2 was indeed a part of the problem. Microsoft released an update a few days ago: KB5058499 (OS Build 26100.4202). “[Graphics kernel] Fixed: An issue where some game titles become unresponsive after upgrading to 24H2.”
  2. Nvidia improved some driver issues, a hotfix shouldbe released soon.
  3. We found that disabling “Hardware-accelerated GPU scheduling” helps.
  4. We were able to mitigate the problem by setting process affinity on the game startup so that the Core0 is reserved for background tasks. We introduced `FWindowsPlatformProcess::SetProcessAffinityMask`

I hope it helps others!

5

Great, thanks for coming back and sharing your results! I have marked your answer as the accepted solution, so that others can benefit from this as well.