Installation or File Error
TruckersMP checks the files in the folder where Euro Truck Simulator 2 or American Truck Simulator is installed.
This error can occur if some game files are missing or corrupted.
Solution:
Verify the game files through Steam.
Then restart the TruckersMP launcher.
Permission / Administrator Issue
The launcher may require administrator rights to access the game files.
Solution:
Right-click the TruckersMP launcher and choose “Run as administrator.”
Mod or DLC Incompatibility
If the DLCs or mods you installed via Steam conflict with the game, you may get a verification error.
Solution:
Remove all mods or disable them in the launcher and try again.
Antivirus or Firewall Blocking
Sometimes antivirus software or Windows Defender prevents the launcher from checking the files.
Solution:
Add TruckersMP to your antivirus exception list.
If needed, temporarily disable the firewall.
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