Red checksum error (Assetto Corsa)

This error usually means one of the following:

Original files are corrupted or modified

Try to verify Assetto Corsa file integrity in Steam - this will restore all Assetto Corsa files to original state. 

Note: this will disable Custom shaders patch, so you will need to reinstall it. Also if you have heavily modified AC - some of the modifications may also be disabled, i.e. sound mods for original AC cars.

Modded files are corrupted

If mod content files are corrupted you will need to reinstall them:

• In WSS app click on menu icon, Game content > Reset game content and refresh page.
• Refresh page in WSS - see if missing content is detected - and install if needed

Real penalty

Server may also kick with red screen if Real penalty is enabled in event and you don't have Real penalty client app active - in this case please see 'Install manually' section here: Real penalty

Custom shaders patch

This error (or "can't compare checksum") can also result if server requires Custom shaders patch (and/or Weather FX), in this case please check this guide: https://docs.worldsimseries.com/article/21-custom-shaders-patch