CIS Firewall Drivers slowed network transfer


I recently upgraded to CIS 6.2.282872.2847 from CIS 5.12.256249.2599. OS is W7. I then noticed the transfer speeds to my NAS had slowed from 10MB/s to 500kB/s when transferring to the NAS. Transferring from the NAS was fine. NAS is wired to router as is the PC

After three weeks of research and blaming my router, NAS, etc, I was looking at the LAN properties and unchecked “Comodo Internet Security Firewall Driver”.

Suddenly i am back to transfer speeds of 10MB/s.

Apart from the relief that i dont have to but a new NAS, I am wondering what is going on. The transfer speeds were fine before the upgrade.

Do i have to leave “Comodo Internet Security Firewall Driver” unchecked? Is that OK?


I believe leaving that unchecked will disable the Firewall protection.

My guess is that something went wrong during the upgrade. Please try reinstalling by following the advice I give in this topic and see if that solves your speed issues.


Alas no luck. I went through the uninstall/re install process three times and each time with Comodo Internet Security Firewall Driver checked the speeds to my NAS (ix2-200) slowed to 500kB/s. Unchecking Comodo Internet Security Firewall Driver lifted the speeds to 11MB/s.

I have reverted to CIS 5.12.256249.2599 and all is OK. Not sure why but at least i am back to where i was.


Did you also run the two CIS unisntaller programs I referenced in Safe Mode? Also, did you run the uninstallers for all other AV’s which used to be installed on the computer, but are now removed?

If not please do. These are a very important part of fixing most issues like this.

If after taking into account Chiron’s considerations the speed problem persists we are likely looking at a bug which needs to be reported.

Please keep us posted.