Go to Settings -> Content Manager -> Plugins and ensure the Steam Integration plugin is enabled and active. Phase 5: The "Clean Slate" Solution
After verifying, Steam will restore acs.exe to v1.163. Now you must tell Content Manager to stop changing it:
If you are an avid Assetto Corsa modder, you have likely been greeted by a message that feels like a slap in the face from your own PC: assetto corsa is obsolete v1163 is required fix hot
The good news is that your game isn't actually broken. This error is almost always a version mismatch or a communication error between the game and your third-party launchers.
In 2026, Assetto Corsa is heavily supported by the community through and Custom Shaders Patch (CSP) . However, the base game itself hasn’t received an official update from Kunos Simulazioni in years. Go to Settings -> Content Manager -> Plugins
If you previously installed certain mods, custom career modes, or no-CD patches, your acs.exe file might have been overwritten with an older version. Ensure you are running the official Steam executable. If verification in Step 1 did not fix it, manually delete acs.exe and AssettoCorsa.exe from your root folder, then run the Steam verification process again to force a clean download of the v1.16.3 executables. To help me narrow down the exact issue, let me know: Are you using the or a different launcher?
If the quick fix doesn't work, or if your game is actually on an older version, try these steps: This error is almost always a version mismatch
If the name of your Assetto Corsa root folder includes non-Western characters (like Chinese, Japanese, or Arabic script), renaming the folder may resolve the issue.
Remember: As both Assetto Corsa receives occasional updates and CSP continues to evolve, these version mismatch errors may recur. Bookmark this guide and keep it handy—you'll likely need it again the next time Kunos releases a surprise patch for the beloved sim racing classic.
A checksum mismatch occurs when a file on the client PC and on the server are not identical. This is particularly common after game updates. When players get this error, the most frequent cause is that a recent Assetto Corsa update has not been applied to either the client or server.