Hi,
How to deal with it because I believe that it was caused by a trusted system process.
You should be able to find the alert in the logviewer.
Go to Defense+ → View Defense+ Events → Push the ‘More…’ button → click on ‘Alerts displayed’
There you should be able to see what the alert was.
The question was that I couldn’t find it in the logviewer because in my opinion all the system services were over and comodo started to stop,so comodo couldn’t record this action in D+.
Ah but you didn’t post that so I couldn’t have know that 
If for some reason cmdagent.exe (CIS main exe) crashed it is possible that all sorts of alerts show up, you don’t have to worry about them because they come from the crash.
After reboot all should be fine.