I upgrade my ubuntu, but the camera applications give me an error message: API mismatch: nvidia....
I find two versions of the nvidia in my system: one is from the ubuntu repository, i.e., nvidia-current. The other one was installed by myself long time ago by nvidia-installer.
The solution for this issue uses the following command:
sudo nvidia-installer --uninstall
Of course, you also can remove the nvidia-current and run nvidia-installer again. For me, the previous one is simpler.