Comodo Firewall Freezes Windows XP When...


System works fine when Comodo Firewall 2.4 is disabled immediately upon reboot. But if Comodo Firewall 2.4 is left running, the PC freezes frequently when accessing files/directories in TrueCrypt 4.2a NTFS volumes. Once frozen, alt-tab or ctrl-alt-delete or power button no longer respond.

NOTE: The problem does not happen after I exit Comodo Firewall 2.4 immediately upon reboot (right-click on Comodo tray icon and EXIT). The problem only happens while Comodo Firewall 2.4 is enabled.


Intel Core Duo (T2300) with 1GB RAM
Windows XP Media Center Edition SP2
McAfee AntiVirus
TrueCrypt 4.2a <— possible compatibility problem with Comodo Firewall 2.4


  1. install Comodo Firewall
  2. install TrueCrypt 4.2a (free) –
  3. mount a TrueCrypt NTFS volume
  4. access files or delete directories in the TrueCrypt volume for a couple minutes
    (doesn’t matter if using Windows Explorer or Command Prompt to access files)
  5. entire desktop freezes, and does not respond to alt-tab or ctrl-alt-delete or even power button (need to unplug and remove laptop battery in order to shut off)


The directory paths use long names and many levels. Perhaps Comodo is hardcoded to use MAX_PATH = 260 instead of the longer limits allowed on NTFS Unicode?

I’m having a similar problem, and also my internet connection (browsing) is very slow when comodo 2.4 is enabled. As soon I disable it, the conection return to normal.

I was using comodo for months and didn’t have any problems until now.

I am also having a similar problem after upgrading from Comodo Firewall 2 to 3. I have mcafee virusscan as well, but not TrueCrypt 4.2a. What I found is when I wait long enough (~5 minutes), the freeze goes away and everything works normal again. I can also eliminate the problem by de-activating comodo or the mcafee on-access scanner. Once I then manually start on-access scan, XP freezes right away. I tried sysinternals file monitor and disconnected network, but was not able to identify what causes the freeze. During the freeze, there is virtually no HD access and the CPU does idle for most of the time.