If a server kicks your custom car with some kind of mismatch or verification error, the cause is almost always a file that does not match what the host is running. Assetto Corsa EVO checks the SHA of mod content when you join a server, and if your copy of a car is even slightly different from the server’s copy, you get rejected.
This isn’t a bug you need to work around with tricks. It’s a deliberate layer that keeps everyone on a server running identical car files, so physics and hitboxes line up for every driver. Once you understand what it’s comparing, fixing it is usually just a matter of getting the right file.
Where custom cars came from and how multiplayer uses them
Custom cars in Assetto Corsa EVO started as a single-player feature: you could drop a modded car into your installation and drive it offline without much fuss. Multiplayer came later, built around the dedicated server launcher. That launcher supports modded car content too, but it layers a SHA verification check on top so the server can confirm every connecting client has the exact same car files it does.
SHA here just means a hash of the file, a kind of fingerprint. If two files are identical, their SHA matches. If one byte is different, the hash is completely different, and the server knows immediately that something doesn’t line up.
What the SHA check actually rejects
Kunos’s own change log for the server tools describes this layer as rejecting modified cars or an incorrect mod version. In plain terms: your file and the server’s file have to be the same release of the same mod. Not a similar version, not a tweaked version, the same one.
So if you ever opened a car mod in an editor and re-exported it, even without touching the physics or the model, you’ve created a new file. It no longer matches the SHA the author originally published, and it definitely won’t match what a server expects. The server doesn’t know or care that your change was harmless. It only sees that the hash is different, and it rejects the connection.
The fix is always the same: get the exact release of the car file that the server is running, not a version you modified yourself, and not an older or newer release from the mod’s page if the server hasn’t updated yet.
Keeping car versions in sync with the host
Mod authors update their cars from time to time, fixing sounds, adjusting setups, or correcting physics values. Every time that happens, a new release goes out, and it will have a different SHA than the old one. That means every player on a server has to move to the new version together. If the host updates the car on their end but you’re still running the old file, you’ll get rejected just as if you’d edited it yourself.
Because of this, a well-run server should tell players exactly which release of a given car mod it’s using, whether that’s a version number, a date, or a direct link to the exact download. If a host doesn’t post that information, your best bet is to ask in their community channel before guessing.
Where the server launcher stores custom cars
On Windows, if you’re running the server launcher yourself, custom cars live in your Saved GamesACE-Server folder. That’s the location the server reads mod content from according to the patch notes, so if you’re hosting and players report mismatches, that folder is the first place to check. Make sure the car files sitting there are the exact release you intend everyone to use, and don’t leave old copies mixed in with newer ones.
If you’re just joining a server as a player, you won’t need to touch this folder directly for client-side issues, but knowing it exists helps when a host asks you to compare files or confirm a version.
Game updates can shift what servers expect
Assetto Corsa EVO is still under active development, and its internal format for cars can change between builds. When that happens, a car that worked fine before an update might suddenly fail the SHA check or simply not load correctly, because the SDK used to export it needs an updated export for the new build.
If you’re using tools to build or edit cars yourself, that means after a game update you may need to re-export your work to match the new expected format. And if you’re just a player who suddenly can’t join a server you were on yesterday, don’t assume the server is broken. Check the mod’s page first. There’s a decent chance the author has already posted a new release that matches the current game build, and the server has already moved to it.
Who’s responsible for what a server runs
Kunos and 505 Games have stated plainly that they don’t endorse or take responsibility for community content that infringes on trademarks or other rights. Custom cars, liveries, and mods in general are created by the community, not by the studio, and what shows up on a given server is entirely the host’s own decision.
That matters for a couple of reasons. First, if a car mod uses a brand or likeness it shouldn’t, that’s between the mod author, the host, and whoever holds those rights, not something baked into the game itself. Second, it means server rules around which mods are allowed, which versions are required, and how updates get rolled out are set by whoever runs that server, not by any official policy. Different hosts can and do run things differently, so what worked on one server won’t necessarily carry over to another.
If you keep hitting rejections across multiple servers with the same car file, the file itself is the problem, not any one host’s setup.
Questions people ask
Why does my custom car work offline but get rejected on a server?
Offline, the game doesn't check your car against anything else, so any file loads. Online, the server compares your file's SHA to its own copy, and if they don't match exactly, you get rejected.
Can I fix a SHA rejection by just redownloading the car mod?
Only if you download the exact same release the server is running. If the author has since put out an update, redownloading might give you a newer version that still won't match an older server, or vice versa.
Where do I find out which car version a server expects?
Check the server's rules, description, or community channel first. A well-run server should list the exact release or link to the download it uses, since there's no automatic way for the client to ask.
Does editing a car mod for personal use always break server compatibility?
Yes, any edit or re-export changes the file's SHA, so it will no longer match the original release that a server is checking against, even if the change itself is minor.
Browse all Assetto Corsa EVO mods on CrashMods
