CIS block Portal without message and only in fullscreen


Got a problem with the firewall and the game Portal (from Valve) : When launched in fullscreen, the screen go black and nothing respond, even Ctrl-alt-del.
When launched in window mode, all is fine, and no alert is needed to be answered (the .exe is set as Trusted application).
If I quit Comodo before lauching the game in fullscreen, no problem, it works fine.
If I put the firewall in desactivated mode, the game still hung.

I use Windows 7 in 64 bits
The firewall is the 3.14.130099.587 free version (no update is available).

It is not the first time I’ve got Comodo blocking a Steam game in fullscreen, but the “Trusted Application” for the exe usely solve the issue.

When going to full screen you don’t see the alerts you need to answer. A known pain in the neck.

When you are sure your system is free of malware you can follow A note to gamers.

I know this (that’s why I’ve launched the game in windowed mode), but I don’t think there is more alerts in fullscreen mode. In windowed mode, there is no alerts and the application is now in Trusted mode.
I’ve tried the training mode before posting there : No change.

It sounds like a compatibility issue to me with Comodo. Try disabling D+ and start the game again.

To disable D+ go to Defense + → Advanced -->Defense + settings → now tick "Deactivate Defense+ permanently (Requires a system restart) " → reboot and try again.

Does this make the problem go?

Yes, with D+ disabled, the game works fine in fullscreen.

Perhaps there are parameters to try in D+, but it will take a long time, because a reboot is needed for each failed test.

Can you start the game with D+ enabled. Can you then show a screenshot of the D+ logs? They can be found under Defense + → Common Tasks → View Defense + Events.