Aero has stopped working after upgrade to V7


i got a strange problem with the latest version of CIS (7.0.317799.4142) and Aero on Win 7 Pro x64.

I have upgraded two devices (desktop pc and laptop) from CIS 5.x to 7. Both are running on Win 7 Pro x64. While the upgrade installed successfully on both machines, the laptop got an issue now. Aero effects are gone there, selecting an aero theme does nothing, it just reverts back to win 7 basic theme. I’m using just the firewall part of CIS and deactivated the other features.

I tried shutting down CIS but that did not help. The only working solution for now is a complete uninstall of CIS, which does restore aero functionality. Tried to do a clean reinstall of CIS too but i keep getting the same issue.

Any help is appreciated.

What video adapter are you using? Are you using the latest version of its drivers? Do the D+ logs give us a clue?

The laptop has a pretty old onboard video adapter from SiS, called SiS Mirage 3 (SiS 771/671). Drivers are up to date. Strange thing is that it worked perfectly with the old CIS v5.

D+ logs show nothing suspicious as far as i can see. Tried disabling D+ / HIPS too but it did not help.

When i look into the event logs of Win 7, i see two related events :

  • Event ID 9007, The Desktop Window Manager was unable to start because WDDM is not in use.
  • Event ID 9009, The Desktop Window Manager has exited with code (0xc00002fe).

If you need any further details, just let me know. Thanks in advance.

Can you check in Device Manager if the graphics adapter is working and active? If not can you see if reinstalling the drivers of your graphics adapter brings a solution.

The graphics adapater shows okay and active in Device Manager. Tried to reinstall the driver too, but it had no effect.

Hi Obi.Wan,
Re-run a WEI assessment.
What is the Windows Experience Index?-Microsoft

If that fails try running the aero troubleshooter.
Troubleshoot Aero problems in Windows 7-Microsoft

Kind regards.

Hello captainsticks,

i did both. WEI assessment completed successfully. The aero troubleshooter detected one problem, it says the Desktop Window Manager is disabled and it has been reactivated. But nothing changes then, aero is still not working. Re-running the troubleshooter gives the same result.

This problem only vanishs when i uninstall Comodo. Still hope there is a better solution than that :).

Hi Obi.Wan,
Please check the blocked files list to see if there are any files related to graphics/display or operating system on the list.
Blocked Files-Comodo Help


Hello captainsticks,

i checked the blocked files list, its empty here.

Hi Obi.Wan,
Sorry none of the suggestions have worked.
I would try running a rating scan and check that there are no files related to graphics/display or operating system on the unrecognized list.
That failing, it looks to be something specific to that system in my opinion.
It might be worth creating a bug report in the hope the Developers can reproduce the issue.
Bug Reports - CIS
Required Format For Reporting Bugs

Thank you for your patience with this issue, it is appreciated. :-TU

Kind regards.

Thanks for your efforts :slight_smile:

I did the rating scan, but no related files showed up in the unrecognized list. I will create a bug report for this issue then.

Thank you.


its me again. Totally forgot to do that bug report, because i had not used the laptop for a while now.

An issue with another software and shellcode injection brought me back to this topic. After some testing i finally found the source of the problem. Looks like the onboard graphics driver is injecting code into the Desktop Window Manager executable and CIS blocks this by default which causes Aero to stop working.

Knowing this, the solution was rather simple then. I added the related windows executable (dwm.exe) to the exclusions for “Detect shellcode injections” in Security Settings → Defense+ → Behavior Blocker and restarting the Desktop Window Manager service afterwards brought Aero back to life! :slight_smile:

Thank you for reporting back Obi.Wan. It may help others in the future… :slight_smile: