.NET Runtime Error
What is this error?
A .NET application crashed with an unhandled exception. Common with games and tools built on .NET or Unity (which uses Mono/.NET).
Common causes
- corrupted .NET Framework installation
- missing .NET version
- game bug in managed code
- mod loader crash (BepInEx, MelonLoader)
- outdated .NET Desktop Runtime
How to fix it
- Repair
- NET Framework via Windows Features
- install latest
- NET Desktop Runtime
- verify game files
Too many steps? Crashless can diagnose this automatically — checks your drivers, temps, VRAM, and 400+ known error patterns.
Get free AI diagnosis Detailed analysis
".NET Runtime Error" or "Application: game.exe — Framework Version: v4.0" in Event Viewer means a .NET application crashed. Many Unity games, mod loaders (BepInEx, MelonLoader), and game launchers use .NET.
Commonly seen with modded Unity games (Valheim, Lethal Company, Subnautica) and tools like Vortex mod manager.
How to fix it:
- Install the latest .NET Desktop Runtime from Microsoft's .NET download page — get both the x64 and x86 versions
- Repair .NET Framework — go to Control Panel > Programs > Turn Windows Features on or off, uncheck .NET Framework 3.5 and 4.8, apply, then re-check them and apply again
- If a mod loader is crashing, update BepInEx/MelonLoader to the latest version compatible with your game
- Verify game files — a corrupted managed DLL can cause .NET exceptions
- Run 'sfc /scannow' and 'DISM /Online /Cleanup-Image /RestoreHealth' to repair system files
- Check Event Viewer > Application for the full exception details — the 'Faulting module' tells you exactly what crashed
- For Unity games, deleting the game's 'Managed' folder and verifying files can fix corrupted .NET assemblies
When to seek help
If this error keeps happening after trying the fixes above, it may point to a deeper hardware or system issue. Consider professional help if:
- The crash occurs across multiple games or applications
- You see the same error after a clean Windows install
- Your PC is less than a year old (could be a warranty issue)
- You smell burning or hear unusual sounds from your PC
Or let Crashless do the deep analysis for you -- our AI checks drivers, temps, event logs, and 400+ known patterns automatically.
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