I have two PC’s that run this combination, with Avast as the AV and Comodo as the Firewall/Defense+ (Comodo’s auto sandbox disabled).
After recently updating Comodo and Avast, noticed that both machines were hanging when programs and files were executed after boot. If you too have this problem, the answer is fairly simple.
The solution was to add AvastSvc.exe to the Comodo Defense+ policy as an Installer or Updater.
This solved all hanging and freezing issues.
I guess it’s always a good idea to exclude Comodo files in Avast and Avast files in Comodo to avoid problems, but as far as I can tell this is the only thing that needs doing for now.
Another minor issue is Avast finds a false alert virus in cmdagent.exe, so you may want to exclude that in Avast to get rid of this detection which appears when doing a maximum level scan.