The error message “Failed to initialize MelonLoader” usually appears when a Unity game fails to start with MelonLoader installed. This message indicates that the MelonLoader runtime could not properly inject itself into the game. There are multiple causes, from missing dependencies to incorrect file placement or conflicting mods.
This guide explains the most common causes of this error and provides accurate solutions.
Common Causes
Wrong Game Architecture
MelonLoader has separate builds for 32-bit (x86) and 64-bit (x64) games. Installing the wrong architecture prevents MelonLoader from initializing.
Signs:
- Game closes immediately
- No console or log appears
- Crash occurs on first startup
Fix:
- Check whether your game is 32-bit or 64-bit. Right-click the executable, select Properties, and check the details.
- Download the matching MelonLoader version from the official sources.
Official sources:
https://melonloader.pro/
https://melonloader.pro/download-melonloader/
Missing Microsoft Visual C++ Redistributable
MelonLoader depends on the Microsoft Visual C++ 2015-2022 runtime. Missing these libraries prevents proper initialization.
Signs:
- Game does not start
- Errors reference MSVCP140.dll or vcruntime140.dll
Fix:
- Install both x86 and x64 versions of the Microsoft Visual C++ Redistributable
- Official link: https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist
Missing .NET Desktop Runtime
Modern MelonLoader builds require .NET Desktop Runtime 6.0 for Il2Cpp games and managed assemblies.
Signs:
- Game crashes during assembly loading
- Latest.log may indicate missing runtime
Fix:
- Install .NET Desktop Runtime 6.0 matching your game architecture (x86 for 32-bit, x64 for 64-bit)
- If unsure, install both x86 and x64
- Official link: https://dotnet.microsoft.com/en-us/download/dotnet/6.0
Incorrect or Missing version.dll
The version.dll file is critical for MelonLoader. If it is missing, corrupted, or conflicting with another loader, the game will fail to initialize MelonLoader.
Signs:
- Crash occurs immediately after launching
- No console appears
Fix:
- Rename any existing version.dll to version_original.dll
- Copy the correct version.dll from the MelonLoader ZIP or installer into the game folder
- Do not place it inside the MelonLoader folder; it must be next to the game executable
Corrupted MelonLoader Folder or Files
Incomplete or corrupted files can prevent the loader from initializing.
Signs:
- Crash occurs during startup
- Latest.log may be incomplete or empty
Fix:
- Delete the MelonLoader folder
- Reinstall MelonLoader using the official installer or ZIP
- Keep Mods, Plugins, and UserData folders intact
Incompatible or Faulty Mods
Some mods may prevent MelonLoader from initializing if they are incompatible with the current loader version or the game version.
Signs:
- Game may crash after showing the MelonLoader console
- Latest.log shows “Failed to load assembly” or dependency errors
Fix:
- Temporarily remove all mods from the Mods folder
- Launch the game with only MelonLoader installed
- Re-add mods one by one to find any problematic mod
- Update mods to versions compatible with your MelonLoader
Anti-Cheat or Security Interference
Anti-cheat software or antivirus programs can block MelonLoader from initializing.
Signs:
- Game closes immediately
- Only occurs in multiplayer mode or with certain launchers
Fix:
- Use MelonLoader only in single-player or approved modding environments
- Temporarily whitelist the game folder in your antivirus if safe
- Check the game’s community rules for modding policies
How To Diagonse THis Error
- Check Latest.log located in GameFolder/MelonLoader/Latest.log
- Look for lines indicating startup problems or missing dependencies
- Test the game without any mods to confirm if the error is caused by a mod
- Verify that your architecture and runtime requirements are correct
Manual Fixing – Follow Steps
- Close the game
- Backup Mods, Plugins, and UserData folders
- Rename version.dll if an old or conflicting file exists
- Delete the MelonLoader folder if corrupted
- Reinstall the latest MelonLoader from official sources
- Launch the game to confirm MelonLoader initializes successfully
- Restore mods gradually
Preventing Future Failures
- Always back up your game folder before installing or updating MelonLoader
- Ensure the correct architecture version is installed
- Keep Microsoft Visual C++ and .NET runtimes up to date
- Update mods carefully and test each mod individually
- Use the official installer to update MelonLoader when possible
Official Links
MelonLoader official website:
https://melonloader.pro/
Download MelonLoader:
https://melonloader.pro/download-melonloader/
MelonLoader GitHub:
https://github.com/LavaGang/MelonLoader
Microsoft Visual C++ redistributable:
https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist
.NET Desktop Runtime 6.0:
https://dotnet.microsoft.com/en-us/download/dotnet/6.0