Yellow Exclamation mark

There’s a yellow exclamation mark over the Comodo logo in the systray. I can’t find a reason for this or what it even means.

That means it reports there is something not right to its installation. Run Diagnosics, it is under More, and see what it reports and if it can fix it or not.

Yep. Already done that with nothing found.

Does Diagnostics report anything as to why it thinks there is something not right?

Do you have other security programs running in the background? Try disabling them and see if that fixes it or not. The same question for network related programs; think Netlimiter, Zenmap etc…

Is this a clean installation or an upgrade from v4.1?

It was an upgrade. Diagnostics found nothing however the exclamation went away after a reboot. ???..??

When it is gone and you see cfp.exe and cmdagent.exe running in Task Manager (with "show processes of all users"enabled) then all is fine. But keep an eye out to see if it returns or not.