Hello @LeonTKM!
Be sure to do this and let me know what happened!
Please ensure that all Roblox files in the AppData directory are removed. To do this:
Uninstall Roblox from your computer
Open the Command Prompt. You can open it by pressing Win+R > Type ““CMD”” > Press Enter.
Type in the following commands:
cd AppData\Local (then press enter)
rmdir /s Roblox (then press enter)
Enter ““y”” when asked to answer (then press enter)
Restart your computer
Reinstall Roblox
I hope I have helped!
Best,
Benjámin