The CUDA Toolkit installer seems to have installed a new driver without removing the old one. Now what?

Accelerated Computing CUDA CUDA Setup and Installation
1

After updating from CUDA Toolkit version 11.5.0 to 11.5.1 with the installer on Windows 10, my development environment is completely broken. I cannot get anything to build with CMake in CLion, and I get a ton of strange PTX runtime errors in Visual Studio. I think this may be because there are two versions of the Nvidia Graphics Driver installed. I only see version 496.13 in Apps & Features (and Programs and Features), but in the Nvidia Control Panel, I see version 472.42 instead. How do I proceed from here?

Update: I reinstalled every Nvidia program (including drivers) at once with the Toolkit installer. While this did fix the discrepancy between the Nvidia Control Panel and Apps/Programs and Features, it did not fix the issue with my environment. As of now, it seems I have no choice but to reinstall Windows.

2

NVIDIA CUDA setup (and even NVIDIA driver setup because they are based on the same proprietary installer written using .Net Framework) will mess up your PATH environment variable. I have reported this bug to NVIDIA in April 2019 if I remember correctly. I am not sure if they ever fixed it or if there is a regression.

Before reinstalling Windows, try fixing your PATH enviroment variable. You can also try repairing / reinstalling CMake, and reinstalling Visual Studio integration.