How to fix error irql-not-less-or-equal in Assassin's Creed Valhalla

Solution Steps

1. 1 Run Assassin's Creed Valhalla as Administrator. Navigate to the game folder, right-click the .exe → Properties → Compatibility → check 'Run this program as an administrator' → Apply. This gives Assassin's Creed Valhalla full system access and fixes permission-related crashes.
2. 2 Update Windows to the latest version. Settings → Windows Update → Check for updates. Install ALL updates, especially 'Optional' driver updates. Assassin's Creed Valhalla requires the latest Windows components for stability.
3. 3 Disable fullscreen optimizations. Right-click Assassin's Creed Valhalla.exe → Properties → Compatibility → check 'Disable fullscreen optimizations' → Apply. This prevents Windows from interfering with the game's rendering pipeline.
4. 4 Install Assassin's Creed Valhalla on an SSD if it's currently on an HDD. Slow disk reads during gameplay cause asset streaming stutters that can cascade into crashes. An SSD eliminates this bottleneck.
5. 5 Check your RAM stability. Press Windows key + R, type 'mdsched.exe' and press Enter → Restart now. Faulty RAM causes random crashes in Assassin's Creed Valhalla that are impossible to reproduce consistently.
6. 6 Temporarily disable your antivirus real-time protection and test Assassin's Creed Valhalla. Add the game folder to antivirus exclusions. Security software sometimes quarantines game files or blocks their execution.
7. 7 Lower Assassin's Creed Valhalla graphics settings temporarily. Set everything to Low/Off, disable Ray Tracing, disable DLSS/FSR. If crashes stop, increase settings one by one until you find the problematic setting — usually shadows, textures, or ray tracing.
8. 8 If Assassin's Creed Valhalla still crashes: uninstall the game, delete all remaining folders in SteamApps\common and %LOCALAPPDATA%, restart your PC, reinstall. This clean slate approach fixes stubborn corruption that verification misses.