¶ Part 1 - Re-verify Steam Files
If you try to join an event and the game gives a checksum error, it's usually because the files your using don't match the ones being used in the server. A quick way to fix this is to verify your files.
How to Verify Your Steam Files in 5 Steps:
- Go to Library in Steam
- Hover over Assetto Corsa and Right-click
- A menu should open up, click on Properties
- Another menu should open up. On the right-hand side, click Installed Files
- Once you do that, a page should open showing you the option to "Verify integrity of game files". Click that option. Steam will now validate your files, this should take around 5 minutes depending on your PC and internet connection speeds. After it is complete, try joining the online server to see if it works.
¶ Part 2 - Reinstall mods
If you are still not able to join the Assetto Corsa server, check if the server is using mods. If it is, then you can try to redownload the mod using Content Manager.
Redownloading mods using Content Manager in 5 Steps:
- For windows, open File Explorer and Content Manager
- In File Explorer, locate the mod that the server is using (I'm using the Formula 1986 as the example).
- Left-click and hold on that file and drag it over to content manager. Drop (release) it anywhere
- In the top right-hand side of the screen in Content Manager, there should be a green icon (See second picture in this post)
- Click on the green icon and it should bring down a page. In that page, your file that you dropped into Content Manager should be shown along with a button that says Install/Update. Click on that and it should install/update the files for you.
Some mods just don't install properly through Content Manager. A manual installation may be required for these. Guide to follow
I hope this helped, but If it still doesn't work, you can always ask in community support or any of the mod team for help.