Assetto Corsa Mods Not Working? Complete Fix Guide

Wrong Folder Structure

The Issue: The most common problem. Car folder needs to be in the right place with the correct structure.

Correct Structure:

Common Mistakes:

• ❌ Putting the car in Documents\Assetto Corsa (WRONG location)
• ❌ Double-nested folders: cars/car_name/car_name/data.acd
• ❌ Entire download archive in cars folder (must extract first)
• ❌ Spelled folder name wrong or has special characters

Missing or Corrupted data.acd File

The Issue: The data.acd file contains all physics data. Without it, AC can't load the car.

Solution:

1. 1. Open the car folder: assettocorsa/content/cars/[car_name]/
2. 2. Look for data.acd file (should be 100KB-2MB)
3. 3. If missing: Redownload the mod—it's incomplete
4. 4. If present but car still won't show: File is corrupted, redownload from source
5. 5. Some mods have unpacked data/ folder instead of .acd—this is fine

Invalid or Missing ui_car.json

The Issue: This file tells AC the car's name, brand, description. Corrupted JSON = invisible car.

Solution:

1. 1. Navigate to car folder
2. 2. Open ui_car.json with Notepad
3. 3. Check for errors:
   • • Missing closing brackets } or braces ]
   • • Extra commas at end of lines
   • • Special characters breaking syntax
4. 4. Use JSONLint.com to validate the file
5. 5. If broken beyond repair, redownload mod

Encrypted/Partial Download

The Issue: Some paid mods are encrypted and need specific files. Partial downloads break this.

Solution:

1. 1. Check file size—compare download to advertised size
2. 2. Redownload with stable internet connection
3. 3. For paid mods (RSS, URD), make sure you have the license file installed
4. 4. Don't pirate—cracked mods often don't work correctly

Wrong Track Folder Location

Correct Structure:

Missing models.ini or surfaces.ini

The Issue: These files define track 3D models and surface grip. Without them, track won't load.

Solution: Redownload the track—these are essential files that should always be included.

Track Requires Custom Shaders Patch

The Issue: Many modern tracks REQUIRE CSP to function. Without it, they won't appear or will crash.

Check for CSP requirement:

1. 1. Look at the mod's download page for "Requires CSP"
2. 2. Check for ext_config.ini file in track folder (CSP indicator)
3. 3. Install latest CSP if you don't have it