If suddently you are not allowed to mount anything on your Ubuntu and you have the following annoying message: not authorized to perform operation (polkit authority not available and caller is not uid 0)
It’s propably that the polkit permissions are mixed up.
After hours of searching the web I found out that I needed to simply uninstalled chrome-remote-desktop.
The solution to fix the problem:
sudo apt-get remove chrome-remote-desktopThanks to the the following video:
