Hey there @NightsGM , thanks for reaching out! It's great to hear you're giving Trackmania a go, but I understand you're having these odd black boxes during gameplay. That's really unusual! Let's sort it out for you
You've already verified the game files, which is great! Please see the rest of our troubleshooting recommendations from the troubleshooting guide. In particular from the guide, please make sure you are running the game with administrator rights, you've verified the game files (specifically in the way we recommend in the guide, just to make sure), you've got your graphics drivers and Windows install fully updated, and you've (at least temporarily, for testing) deactivated all background programs.
I'm confident that'll fix the issue, but please let me know if not. In that case, it'd be really great to have a screenshot. Here's our screenshots guide, and the resulting images can be added to a response here in the forum thread using the little image icon above the post edit box.
Let me know if I can clarify any of this