Comodo Block Loopback Connection? [Resolved]


I’m trying to solve the mystery of XPCOM:Event Receiver error message. I had them on my old PC. They escalated, & eventually I was unable to run Firefox. Your security solutions close down, but the computer doesn’t because firefox.exe keeps running. Now on another computer I’ve gotten this message!

I’ve found instances online of this error message that date back long before Comodo, so at first I dismissed any notion it was FW related. I did wonder if my denial of a FW alert may have set things in motion. When I’m not sure, I choose no! Both these PCs had Comodo on them. I love Comodo!

What do you think? This is a quote from Mozilla:

Outpost Pro Firewall, versions 2.7 and 3.0, can cause Firefox to stop loading Web sites. The “firefox.exe” process may also be left running after closing Firefox, and shutting down the computer may be blocked by an error message that the XPCOM:EventReceiver is still waiting for data. This may be due to blocking the loopback (localhost) connection.

It’s a possibility, isn’t it?


Adding a link to the original–it has links!

Hi Michele. I use Opera browser and it also requires TCP loopback in order to function properly. If you go to Application Monitor and see any blocked incoming connections, remove them. To avoid such alerts in the future, just enable the Skip loopback (127.x.x.x) TCP connections in Security > Advanced > Miscellaneous > Configure… > Check to enable the 2nd option. See if that works for you.

Help file:
“Loopback connections refer to the internal communciations within your PC. Any message transmitted by your computer through a loopback connection is immediately also received by it. This involves no connection outside your computer to the internet or a local network. The TCP option is not checked by default because, in the case of someone using a proxy server, there is a higher chance of attacks being launched using a loopback connection.”


I love you guys! Immediatley you know what to do! I’ve ticked Skip Loopback TCP. I’m going to post your solution on Mozillazine so no one else will watch their PC come apart when all they have to do is tick! Thank you so much!


Great that it worked out (:HUG).