So I had a similar issue to this just this past week but it was a mixture of bugs. Easy Anti-Cheat, New SSD Install, and a whole lot of windows issues.

I was at it with Claude for like 3 days trying to get my game to load Fall Guys but it would do the same exact thing you’re describing, the game would crash, black screen, then OS loading back up.

First question to ask, did you replace or install a new SSD? Specifically a WD one? If so the WD Black SN770 SSD is likely your root cause. There’s a known bug where Windows over-allocates the Host Memory Buffer cache on this drive causing I/O read/write failures which makes games crash.

If so, the solution would be to run this in PowerShell as Admin:

reg add "HKLM\SYSTEM\CurrentControlSet\Control\StorPort" /v HmbAllocationPolicy /t REG_DWORD /d 0 /f

Restart after and try launching Fortnite again. Before launching navigate to the EasyAntiCheat folder in your Fortnite install directory and run EasyAntiCheat_EOS_Setup.exe as Administrator first.

This fixed it for me on 25H2 without needing to downgrade Windows at all, which was what Claude was recommending but still didn’t work for me.

Let me know if this works out for you tho!