Accidentally blocked Windows update. How can I unblock it?

Hi. I’m using Comodo free version 5.5.195786.1383. During an automatic Windows (XP) update I accidentally clicked Block when promted to block or allow, and now I can’t install the update. Windows keeps trying, and I’ve gone to the Windows update site to do it there but it continually fails. It was a high priority update so I need to install it, and I’m worried all future windows updates will be blocked as well.

I’ve tried turning Comodo off by right clicking the system tray icon and selecting Exit. I’ve tried disabling the firewall under firewall behavior settings, and I’ve tried adding windows updater applications under Define a New Trusted Application. The update is still failing.

Is there anything I can do short of uninstalling Comodo completely?


Just FYI, selecting Exit from the tray icon only closes the user interface. Your system is still protected, you just have no control over CIS.

It sounds like it’s actually Defense+ doing the blocking if disabling the firewall and adding the updater in the firewall as a trusted application has no effect.

Go to Defense+ → Computer Security Policy → Blocked Files. Just remove the updater if you see it there. Don’t delete, just remove.

Thanks for your reply. Blocked Files is empty.

So if you go to Firewall → Network Security Policy → Application Rules, do you see anything that is listed as Blocked Application?

Yes, under Comodo Internet Security it says block and log all unmatched requests.

I meant Blocked Application, under the Treat As column.

That is normal for CIS and wouldn’t be blocking Windows Update.

Since these are the only two areas where blocked applications would be, I’m not sure what to tell you. Could you attempt an update and post screenshots of your Defense+ and Firewall events?

Hi again. The firewall events page is empty. This is the defense + events page. The update in question is the very top entry (hopefully you can see it). I wondered if it might not be the firewall at all and just some problem with this particular update. Or maybe it would be simpler to uninstall Comodo then try it, then install it again. I should probably get the lastest version anyway.

Sorry I am not currently at home so I cannot run through the process step by step. But, you want to check under Computer Security Policy (Defense+). There are two areas you want to check: Defense+ Rules and Blocked Files. Edit (or remove) any rules regarding the Update to allow and if on the Blocked Files list remove it. You can also try disabling Defense+ to install the update until you get a more precise fix. If after disabling Defense+ you are still unable to install the update, try checking the box “Deactive the Defense+ permanently”. It should require a restart. Install your updates and then reactivate Defense+.

Also, most like the files you need to be adding to trusted, are those listed in your Defense+ Event log starting with “C:\WINDOWS\SoftwareDistribution\Download\4”. These are the update executables that Windows Updater or yourself is trying to execute and getting denied. These are the files you do not want in the listing I mention above (unless you set it to trusted, etc.). Sorry I am being kinda vague but I dont have access to Comodo on this computer.

I doubt it is the firewall in Comodo because it appears the Update files have already been downloaded.

Checking Deactivate Defense + Permanently did the trick (and yes I’ve unchecked it again). Thank you very much both of you, that’s a relief.

Hopefully it won’t block future updates.

Thanks again.

I dont believe it should give you anymore problems unless you uninstall that particular patch and try to reinstall it as what you blocked was likely the executables for the update rather than windows update.

Im glad that solution worked for you. I would still suggest trying to find where you blocked it and remove those settings.

You got a popup for windows update? I never got any popup for any windows update with default settings of CIS Full Suite.

Check FW & D+ i.e

Network Security Policy - Rules other than the default rules or rules on the top or bottom or post a screenshot here.

Computer Security Policy - Rules other than the default or rules under all application or the rules on the top or post a screenshot here.


Hello Phil5000,

From your Description I think I could help.

Could you do me two things, 1) Open CIS > Defense+ > Defense+ Events > More > Displayed Alerts > File > Export > Save as HTML (Upload it on your next reply)
2) Start > Right Click Computer > Manage > Event Viewer > Right Click Application > Save Log File As (Once Saved Do the Same for System) Upload both on your next reply)

What update are you trying to apply? (KB# would be great!)
Do you have any other security software installed?