I always have a red circle in the upper part of my Ubuntu 16.04 screen, and whenever I click it, it says the following:
I can tell that Mono is a cause of this problem; I tried to uninstall it but it didn't seem to work! I can't even reach synaptic!
sudo apt update
on a Terminal to see in detail what the true problem is. There you should be able to spot the errors listed at the end of the process.sudo apt update
?