If you get this error in your logs:
add bridge failed: Package not installed
This error normally means one of two things.
1.) Is your brctl (bridge-utils) installed?
On Mint/Debian check for "brctl". If it's not there do
sudo apt install bridge-utils uml-utilities
2.) Is your bridge.ko (bridge kernel module loaded?).
On some installs I have seen that you cannot modpro........