Comodo Firewall – Problems After Two Weeks of Use

Well I am sorry to report that the Comodo Firewall I had previously installed and which I had written about starting acting up on my system this week.

All firewalls require a learning period in which the user is asked if they want to allow certain programs on their system to access the Internet or other network computers. And so it went with Comodo. Except the software asked me if I wish to allow Firefox, my main browser, to access the Internet and I answered yes each time. I thought something was wrong, because every time I open Firefox, I got asked the same question.

So on Thursday morning I fired up my system and I was unable to connect to the Internet. I spent 20 minutes going through the normal diagnostics, including the repair option built into Windows XP. I also restarted both my cable modem and router. Still nothing. I then tried two of the other computers I have at home and both connected just fine to the Internet.

That is when it hit me. Could it be the Comodo Firewall? Sure enough, after I disabled the firewall I was able to connect to the Internet. So with reluctance, I uninstalled Comodo.

In all fairness, Comodo is not the only firewall that has this problem. I also had a similar situation using the free version of Zone Alarm on my wife’s computer. Again, all was well after I took Zone Alarm off.

I have read other similar reports concerning both McAfee and Norton having problems with their firewalls as well.

Am I done with Comodo? Nope. I’ll wait for a upgraded version and take it for another spin. :-)

[tags]Comodo, firewall, uninstall, internet, no connection, zone alarm, norton, mcafee[/tags]

Article Written by

I have been writing for Lockergnome for eight years.

  • Marc Klink

    I had used this also, and come to a similar conclusion after not being able to get mail on one machine, and not being able to browse on another. However, on each of the machines everything else was ok. Back to Sygate for now. One last thing… someone with some pull needs to have the nice people at Comodo put some work into their uninstall routines, because they truly suck.

  • S P

    I have been using Comodo firewall since version 1.0. I have not had any issues with it blocking Firefox or any other program that I did not want it to. In fact I installed it on my Dad’s PC (he is not computer savvy at all) and he has not reported any problems with it either. The product has improved a lot since the earlier versions and I even sent a message to the creator through the Comodo forums thanking him for the effort he has put into it. He replied quickly and seems like friendly person. IMHO it is the best free firewall avaliable. So I look forward to the future enhancements to this Firewall and will continue to use and recommend it.

  • Pat Veach

    Same problem. Among other things, it doesn’t play well with remote desktop services. The worst aspect is, as reported above, it fails silently. You don’t know you are being blocked. If you try to use remote desktop to ‘allow all’, it won’t do it and it won’t tell you it won’t do it. It won’t allow some programs even if you explicitly order it to allow those programs and again, it remains silent about it. No doubt very secure, but very hard to work with.

  • Shadesman

    I recently installed Comodo as I was sick of the ever more bloated Zone Alarm falling over whenever I used a P2P application. However I’m rapid;y losing patience with Comodo (which in most respects seems to be a nice piece of software) due to it’s stubborn determination not to allow me to use Firefox. I’ve lost count of the number of times I’ve told it to allow Firefox to access the net (and remember that I’ve allowed it), yet periodically it will come back and ask me yet again. Damned annoying!
    So it looks like I’ll be going back to Zone Alarm

  • cal

    God what a nightmare I am having just trying to get rid of this program, its like the plague. I cant uninstall via the CP add/remove, I tried opening it again and know it gets stuck in a loop and tells me that i have to reinstall it but first i have to uninstall the first attempt (does anyone see the catch 22 here). i am now going to where few truly love to enter to rid myself of this beast and that is the registry. I’m going to do that before I go through the headache of a rollback cause i’ll end up in the registry anyway and not for just one program but all the others.
    To those of you that love the FW, more power to you. I just wanted to use the PW vault, as my system is safe and I just wanted something that I could through on a flash stick and take with me for my PW. All I can suggest to you is never try and delete any of them.
    To the one guy who got it off after a battle why on earth would you give them another chance (lol).
    Mark man I agree with you, they suck and they need to do a lot of work on it but i’ll not give them a chance to do this to me again. Once burnt and all….. take care.

  • Nick

    It may be that the signature (i.e. version number, hash, etc) of your browser changed, perhaps from the installation of an extension and that the browser was then blocked by comodo, either by a direct user blocking or by comodo’s inbuild rules. You can always check the status of an app in the settings.

  • Ron Schenone

    Hi Nick,
    Thanks for the suggestions. This occurred using I.E., Firefox and Opera. And I wasn’t totally surprised by this event. I had similar problems with ZA as well. My best guess is that it most likely is a router issue when new network addresses are assigned. Just a guess.

    Anyway, being behind a hardware firewall and using the built-in firewall from XP, seems to work for me the best thus far. Fingers crossed.

    Thank you for your comments, Ron

  • Svilen Yankov

    I am using one lan card for conecting to internet via wireless odem and to work net. Firs i used ZA but after trying t remove a program from its list it went crazy. Then I installed comode and after that I have very offten pproblems connecting to nternet – asignes wrong IP and very often have problem connecting to server in work. When I “Allow All” the it is fixing the problems – no firewall at all. I tried to allow specifialy the server IP in the network monitor but did not help. Anyone to advise what to do

  • Ron Schenone


    Try this link. Comodo has a user manual in .pdf format that may help.

    All the best, Ron

  • Dany

    My bad, corrections:

    1) Select “Security” tab (on top)
    2) Select “Advanced” tab on left
    3) Select configure under “Advanced attack Detection and Prevention”
    4) Select “Miscellaneous” tab
    5) Uncheck check box “Block fragmented IP datagrams”

    Sorry for the mistake.

  • Ron Schenone

    Hello Dany,
    Thanks for providing this information. I am sure it will help someone. Again, thanks for the comment.

    Regards, Ron

  • webmasta

    I am so sick and fucjkign tired of comodo popping shiyt in my face about different programs trying to use the browser to connect to the internet — have a few progs open notepad being one of them … then all of a sudden comodo says notepad MAY be trying to use IE to access the internet, notepad?? .. comodo seems like one of those pesky snoopy employees that runs to the boss with every little shiyt hoping to gain points … it gets its first flying lesson as soon as I am done with this comment .. right through the fucjkign window….

  • Ron Schenone

    Hi webmasta,
    It doesn’t sound like your experience with Comodo has been to pleasant. :-)
    Thanks for your comments, Ron

  • melster

    Have a question for you. I have took out all Norton products on my system and keep getting the NIS for a firewall. How can I get rid of this due to having two firewalls showing up @ the same time. And yes, I have gone through their removal process but it still won’t rid the “varmin”. :)

    All help is appreciated!

  • Ron Schenone

    And you used the Norton removal tool as well?

  • Steve James

    I gave Comodo 2.4 a try and it trashed my registry.
    XP was able to recover an older registry, but many of my settings were lost.
    I will not be using it again.
    I use the old Sygate Personal Firewall just for controlling outgoing applications. I’m behind a router.

  • Ron Schenone

    Hi Steve,
    Thanks for your comments and sharing your experiences with us.

  • Bruce51

    My problems arose after only a few days of use. I would lose internet connectivity during a normal session. The Time-Warner diagnostic routine would flag my system as having changed from dynamic to static access. I couldn’t confirm this by viewing my network adaptor’s properties however…all looked normal there. Running the repair would correct the issue tempoarily. Other times it would diagnose corruption in my TCP stack and it was unable to effect a repair. I would have to reboot my modem, reboot my computer and/or run the XP network repair to correct the issue. This got old fast. I uninstalled Comodo and reinstalled ZA free. This helped, but the issue would intermittantly crop up. I finally ran a System Restore point to completely resolve this…although strangely, the restore point I took at the Comodo install was not useable.

  • Ron Schenone

    Hi Bruce51,
    Thank you for sharing your experience with us. It is appreciated.

  • simone

    I had the same problem with Firefox and…no way to make it work!

    I found 3 workarounds:
    a. Allow All traffic from Comodo (which means no FW at all!)
    b. Turn-Off Comodo Application Control Rules (sounds still very unsecure)
    c. Delete Firefox-related Application Control Rules and let Comodo to learn by asking you again (recommended)

    IMPORTANT: close Firefox to allow Comodo to learning again about it. I spent hours enabling manually any possible traffic for Firefox in Application Control Rules and I didn’t manage because Firefox was still open.

    I adopted c. also with Voipstunt as my wife blocked it accidentally and it worked fine.

    Hope it will be useful to somebody


  • Ron Schenone

    Thanks Simone!

  • Sico

    I agree, thanks simone :). You helped me!

  • Unclown

    Re: this post:

    5) Uncheck check box “Block fragmented IP datagrams”

    This worked for me.

    Http traffic didn’t work on new dial-up account (ftp worked (well, just browsing the ftp server, didn’t try downloading)).

    Disabling/exiting Comodo had the ‘Net working perfectly, so it was the firewall that was having difficulties.

    Disable “Block fragmented IP datagrams” as per Danys’ post.

    HTH someone.



  • Ron Schenone

    Hi Unclown,
    Thanks for the info.

  • don

    tried comodo as I was concerned as I felt zonealarm was using lot of memory. .After few days lost connectivity on my broadband. Attempted repair, changed cable, checked connections. Fixed when i disabled fire wall so have removed and gone back to zonealarm with no connection problems.Also had problems with zonealarm pro so am back to free version.

  • Howard

    For the past week(s) Comodo has driven us nuts with its continuing to learn after upgrading to version 3. I never thought it would end! Repeatedly I responded to allow it to access Mozilla and many other items and it apparently refused to stop with the messages inquiring about allowing them. E-mail was especially a bother. I wish I could tell you what has now caused it to relent and start to cease on some of these. I came very close to uninstalling it. I never found these problems with the previous version.

  • Howard

    I found the cause of my problem with Comodo! When I first installed Comodo 2 I also installed an anti spyware utility with it. After I installed the version 3 if Comodo, the anti spyware utility went into overdrive and caused all of the problems for over a week. After uninstalling the affected spyware software, there have been no more bothersome pop-up screens. I was just a little dense and didn’t take the time examine these screens. Comodo 3 is a great firewall.

  • TT

    I have some similar problems, but with Sygate personal firewall.

    If you use P2P program over night and try to surf on net at the morning, the Sygate Personal Firewall program freezes firefox and IE traffic. SPF dosen’t recognize firefox or IE program at all and so it dosen’t allow it to access to net. Even restarting the program dosen’t help, you need to restart whole windows or shut down SPF to surf on the net.

    Zonealarm free version has been working well, but i’m not satisfied to how it controls svchost.exe traffic. If you block svchost traffic, you can’t surf on the net. If you allow it, it will make unneccessary access to net and downloads, even if you turn off windows automatic updates from services.msc.

  • Ron Schenone

    Hi Howard,
    Thanks for letting us know and I am glad you found the problem.


  • ro

    First time I install Comodo latest version today. I installed it without defense+ since in my ignorance I think it is too much. I use avast as an av.
    I just gave aceess to first pop ups from firewall and allowed programs I use usually like utorrent, emule, soulseek.
    I use it in Train with safe mode. No problems whatsoever. No slow surf nor downloading torrents. Perfect.

    Am I missing some configuration? at it shows stealth mode for all ports.


  • Tim

    Fixing the Uninstall issue
    This seemed to last at least a year in the forums.
    Does it uninstall properly now? If not why not bundle a link to a
    file to download that gives all the methods ?

    I had security centre telling me it was not running after it was uninstalled
    (it was gone from program files). Annoying but not a dissaster


  • T

    Ho yea!!! Unflippen real. Before I slam COMOHOMO I have to say this, Sygate is dead. If you like using 4 year old software, please continue to use it. No updates since 2004 when NORTON bought it!!

    COMOHOMO locked it up good! I’ve used just about every software firewall there is for the last 10 years & none have done this. I decided I’d do the expert install! HA! Trouble is that it locked me out of everything. I couldn’t even shut down my machine. NOTHING worked, no programs, nada. Hard boot & F8, safe mode, uninstall!! Thank GOD it it let me back to have “permission” to my PC!

  • Fibo

    Hi, I have just installed Comodo firwall but can and comodo antivirus but anyone please tell me how I can get it to allow my outgoing emails. I have enabled the allow application for Outlook and I have tried all manner of other things but still they cant be sent, I just keep getting administration system messages. I wish I had stuck to AVG firwall now. Please help me.

  • jazz

    What a load of crap this Comodo firewall is. Uninstall you BAS***D!!!. No wonder it is free! once it’s there there is no getting rid of it, it really fu**s your machine up. Are the programmers thick or what?, how many times have they been told about this issue but still do f**k all about it!!

  • Gazz

    To remove COMODE FIREWALL made simple for beginners.









  • hopeless

    Running comodo firewall for a couple weeks now and was mostly liking it, after a long running NIS nightmare that Norton premium support could not even fix on their nickel. Just now gave a new trusted executable (that does run OK on my other systems) permission to run and system went crazy. Cannot run anything now. All access to any program, picture, doc, control panel, regedit, etc is denied with “cannot access the specified blah blah as I do not have the permissions” and so on. Well i am the only user and also admin.

    I can’t even shut the thing off, as I do not have the permission to do that either.

    Can’t uninstall anything, can’t run anything,and can’t shut it off. I’d say this firewall works pretty well… Worse yet, the only pc I now have that works is my wife’s Vista machine that i’m typing this on… Open to suggestions.

  • Pingback: Vangelis and firewalls « DJ’s *new* Weblog()

  • Arch Parsons

    I can’t recall having more problems installing a piece of software in more than 25 years! It looked nice and I hoped it would work. First I got a Blue Screen of death each time I tried to use a browser. Then I found it was not listed in the installed programs list so I had no way to uninstall it. I won’t go into all the rigmarole I went through to get rid of it but I will say I was grateful when it was gone. It’s so nice to have Zone Alarm Pro working so inconspicuously. I can only assume it was incompatible with Avast 4. What a pain in the ass!

  • pjmcke

    I am having the same permissions crap and there seems to be no way around this. Cannot go ito registry or add remove or go into administrativve services. Any help would be greatly appreciated

  • vataoman

    Yesterday after two weeks of pretty solid performance from 3.0.21, I found I couldn’t run a single program in my start menu. Everything just gave the error ‘don’t have permission to access’. Trying to view or modify the executable or re-take ownership gave the same result. Being a domain admin, I checked the permissions on the executables and everything was hunky dory. After some small amount of panic I also realized AVG and BOClean icons were not in the tray and the comodo icon wouldn’t accept a right click. I remembered the ‘my safe files’ list or whatever it’s called and suspected this ‘feature’ which I have never actually used. Into safe mode as local admin, uninstalled comodo and presto-changeo, I have a working machine again. I have machines with ZA free and ZA pro as well as Symantec and have never run into this before. I am seriously disappointed. I am going to install it again (they have a name for people like me..) and try to keep better track of what happens when. Thanks for providing this space.

  • vataoman

    Aha, just found the post in the forum about comodo locking out explorer.exe. Could certainly have been the cause of my problem. Hmm, can’t run it because I can’t change it, can’t change it because I can’t run it. Now I want to see if I can get ZA to do the same thing 😛

  • Ana

    I had right now the same problem of the “no permission” stuff with Comodo firewall.
    I have been using this firewall for about 1 or 2 years and it was working great until today. Today I have updated the version of the comodo firewall and when it asked me for a reboot and the system came up running again, it started to ask me about the program permissions that I was running. I was giving permissions to all programs, since I trusted them, and then after giving permissions to iexplorer or firefox the firewall went crazy: I couln’t open any program, couldn’t uninstall stuff, couldn’t shutdown the pc, couldn’t configure anymore comodo firewall.. just like other people described here.
    I am using the administrator account with windows XP SP2!

    Then I took the suggestion posted above: hard shutdown the pc + F8 to run in safe mode + unistall comodo firewall.
    I did it and now the system is working fine and I turned on the windows firewall (better than nothing! :P)

  • Ron Schenone

    Hi Ana,
    Thanks for sharing this with us. It is appreciated.
    Regards, Ron

  • Jacki

    I had Comodo for a few months. It was great….then my connection stopped working….like totally. I could not system restore, could not stay online for more than 1min 20 sec (confirmed by ISP) & then whoa I did 2 fresh installs & installed Comodo (it was great till that point) Helloooo I found my problem. Pity I can’t find one like that though…..have to suffer with the XP one ….. great work comodo.

  • fritzy252

    Hi This has probably already been addressed but I’ve spent most of the day trying to reinstall the newest version of Comodo firewall. At the end of the installation a messege comes up saying…….

    “COMODO Firewall Pro Installer Problem with deleting the Shortcuts. Please kindly delete the Shortcuts manually.” then immediately rolls back.

    This keeps happening when I try to install it. I tried the method GAZZ suggested but made no difference just refuses to install without rolling back every time. I love this firewall due to it’s light resource consumption. but doesn’t to be a bit of good if I can’t install it.

    Anyone have any suggestions how I can get it to install. I just reinstalled a new operating system XP -w sp3 and don’t want to redo the whole entire bloody thing again. Thanks in Advance

  • LLeong

    Hello, used to use zonealarm, but that became bloatware and its effectiveness has lessened. So i switched to comodo v2.4. That ran well with my 3yr old hp compaq tablet running XP SP2. No conflicts with Avira or anti-malware progs or browsers (IE, FF, Opera). 2 days ago, i installed comodo v3. Fortunately i set a restore point before the installation. After i installed, i upgraded my spywareblaster, and some bluetooth installer kept popping up. Also, i counldnt access my wireless LAN the next day, despite setting the restrictions on CFP to nil. Worse, all the desktop icons were frozen in place and i couldnt move them… Uninstalled CFP 3 and did a rollback. I may try again later after having upgraded all other programmes first… and set a restore point. stick to v2.4

  • Jack

    After reading reviews on Comodo I thought I had found the right firewall. I’m using winxp sp2. After just 2 weeks of annoying requests for approval (which I accepted as part of the price to have a great firewall) I was installing an application yesterday and I told Comodo to treat it as an isolated application then – BANG – everything is locked. No warning from comodo that I might have been doing something wrong or dangerous – nothing!! I can’t get into comodo to change config I can’t open any other file or application. Can’t even shut down because I don’t have “permission” for anything.
    Have tried starting in safe mode but unfortunately it still won’t let me do anything let alone uninstall comodo.
    Looked good but I’d rather suffer with one of the other firewalls. Anyone know how to get back into the machine? Appreciate any help.

  • Bjorn

    Experienced the same problem as above with Comodo/isolated – no solution here yet – but as I’m on a Thinkpad I have access to data on the harddisk from the Rescue & Recovery area –

  • Jim

    Same thing happened to me yesterday on a Vista laptop – decided to mark a program as an isolated application and everything locked up. Hell, I had a nice shiny new laptop and thought the days of forcing a shut down by removing the batteries was in my past, but the bloody thing even told me I didn’t have permission to shut down my own computer!
    I restarted in safe mode and logged in to the pre-installed administrator account, went to control panel and un-installed the Comodo program, rebooted as normal user and , TG, all was OK.
    What I’m wondering is, what did I do wrong and, secondly, why didn’t Comodo stop me if the consequences are so disastrous. It doesn’t bear thinking what an inexperienced user would do in such a case.

  • grey

    pls. also having a problem with comodo firewall after i updated it and restart my pc then now i dont have permission to access any of my installed programs in my pc…

  • Kerry Marsha”

    posted by “F”

    “COMOHOMO locked it up good! I’ve used just about every software firewall there is for the last 10 years & none have done this. I decided I’d do the expert install! HA! Trouble is that it locked me out of everything. I couldn’t even shut down my machine. NOTHING worked, no programs, nada. Hard boot & F8, safe mode, uninstall!! Thank GOD it it let me back to have “permission” to my PC!”

    Just the same problems for me! What a piece of SH*T this firewall is! It locked up EVERY EXECUTABLE, including the button to “Add/Remove programs”, so I couldn’t uninstall this malware, had to reformat & re-install, and went back to “good old Zone Alarm”.

    I just love the blurb on Comodo’s website telling me how fortunate I am to have this “professional” product for free. Kiss my butt!

  • Steve

    I used Comodo after years of peaceful coexistence with Zone Alarm Free, since it was recommended by a PC mag, that questioned ZA’s ability to hanble XP SP3. (wrong)

    Boy, what a mistake! As others say, it wants me to authenticate every f*ckin’ exe ( hey, I just want a bloody firewall, mate..OK? ) and then locked up EVERY .EXE on my machine! Including the one behind the “Add/remove programs” button, so I couldn’t uninstall it! WTF?!!!

    I reformatted, reinstalled XP, and installed ZONE ALARM FREE. My “old girlfriend” took me back without a murmur, and now we’re very happy together.

    COMODO is mal-ware. What’s hilarious is Comodo’s home page explaining how lucky I am to have such an advanced piece of programming excellence FOR FREE! They’re dead men walking.

  • Peter

    Comodo has been doing the denying permissions trick with me BIG TIME. I cant access much of anything-I cant run anything except the cntrl-alt-del screen (where I can at least turn off or restart my pc as it wont let me do it on the start menu). I cant change anything on my hard drive (so I cant remove it), cant run add remove progs, yse comodo or use the comodo uninstall. I tried going into safe mode and all I get is black screen with white text listing windows system drivers!
    Like a fool I asked the guys on the comodo website chat page for help-and just got told that I had to pay for the full version for them to help me remove their blasted software and get my PC running again!

    This is the single worst experience I have ever had with a piece of software (ironically far far worse than anything that ever happened to me due to a virus).

    Any suggestions?

  • .KT

    I had exactly the same problem Ron had

    I was using Sygate Personal for the last say 2 years n had not one problem.. I was all happy when all of a sudden my broadband stopped working.. I kept cursing my service provider for almost a week and never thought it could be my firewall, which I have been using since last 2 years , causing me actualy problem.. Once I find out its Sygate, I uninstall it and start working on Comodo.. Works fine for like a week when I again have the same problem where I just cannot to anything on the internet.. Now have disabled firewall..

    One of the solutions above suggested (by Dany) didnot work :-(

  • Bohdan Paszkiewicz

    I have been using Comodo v 3.8.65951.477 on Windows XP SP2 for some time now. Recently I have decided to upgrade to version 3.9.95478.509. After the upgrade, when I boot the system, the blue screen flashes and the system reboots. The only way to stop it, is to pull the plug out and remove the battery. Fortunately, I made the backup before the upgrade. So I reverted to the older working version of Comodo.

    I tried to contact Comodo and found out that on their pages they do not provide any facility to contact them by e-mail. At the same time I found out that they heavily promote the paid version of their software.

    With such approach, I find that a little bit too opptimistic on their part.