How to remove avast! Online Security from Firefox

Martin Brinkmann
Mar 17, 2014
Updated • Feb 15, 2016

Nowadays when you install a security suite, no matter if it is free or paid, it is likely that at least one browser extension is added by it during installation to popular web browsers such as Firefox, Internet Explorer or Google Chrome.

When you install the most recent version of avast! Free Antivirus, the company's avast! Online Security extension will be added to the browser (it is also added if you install a paid version).

It has been designed to add protection to browsers specifically, and will warn you about phishing and malware sites while you are using the browser.

The extension has caused issues in the past for Firefox users, slow downs for instance or lag experienced while using the web browser.

While it is possible to disable the extension in Firefox's Add-ons Manager, there is no option to remove it completely from the browser.

avast online security uninstall

The extension won't be loaded if you hit the disable button, and while you should see improvements right away, you may want to remove the extension completely from the Firefox web browser if you do not plan on using it ever again.

Tip: I have explained the method to delete Firefox add-ons without remove button here in detail.

The avast! Online Security extension for Firefox is not loaded into the profile directory of the browser. As you may know, there are other locations where extensions may be placed in to be loaded automatically by the browser.

It is also not located in the main Firefox installation folder on your drive. So where it is then?

You find the avast! Online Security add-on in the main Avast Software folder on your system under C:\Program Files\AVAST Software\Avast\WebRep\FF\

Note: before you go there, you need to disable the self-defense mechanism of the Avast application running on your system, or quit it, or remove the folders while booting into another operating system as they are protected otherwise and cannot be removed.

To disable the self-defense mechanism, do the following:

  1. Open the Avast software interface on your system.
  2. Click on the Settings link in the left sidebar.
  3. Click on Troubleshooting after the avast! Settings open up.
  4. Remove the check mark from "Enable avast! self-defense module".
  5. You will receive a warning message, continue here.
  6. Avast displays an on-screen prompt afterwards where it wants you to verify that this is intended.

The self-defense module is disabled then, and you can remove one or all of the extension folders under the WebRep structure afterwards.

When you have deleted the FF folder, or moved it to another location for safekeeping, you need to restart Firefox to complete the removal.

When you restart Firefox afterwards, the avast! Online Security entry is gone from the browser.


avast webrep

So how did the avast! Online Security add-on get installed in first place if it is not located in one of Firefox's traditional add-on locations?

The answer is by using the Windows Registry.

  1. Use Windows-R to bring up the run box, type regedit, and hit enter.
  2. Navigate to the key HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Mozilla\Firefox\Extensions using the folder structure on the left. This is the path for Windows 7, other versions of Windows may use HKEY_CURRENT_USER\Software\Mozilla\Firefox\Extensions instead.
  3. Here you find the avast! extension listed, and this is how it gets installed in the browser.
  4. The preference links to the folder where the extension is hosted in.
  5. You can remove that key to delete it from Firefox as well, but that requires a restart of the browser.

Note: Updates may introduce it again to the browser.

Uninstall avast! Online Security add-on from Firefox
Article Name
Uninstall avast! Online Security add-on from Firefox
A guide that walks you through the removal of Avast's Online Security add-on for the Firefox web browser.
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  1. Doug said on February 15, 2016 at 9:28 pm

    Thank You, I’ve searched and searched and you finally gave me the answer I was looking for. I can’t believe all the sites I tried to just get a simple answer; about 25 at least. I will come to from now on to get my advise.

    1. Martin Brinkmann said on February 15, 2016 at 10:02 pm

      Doug welcome and thanks for the praise :)

  2. Linda Lee said on November 26, 2015 at 6:34 pm

    Thank you. I came here because I was so mad with that safeshopping thing they added that I wanted to get rid of them entirely in my browser.
    Worked like a charm!

  3. Smarsh said on October 24, 2014 at 3:11 pm

    Great post – thank you!

  4. eumel said on September 6, 2014 at 5:32 pm

    You can remove this addon in a quite simple way: install the program toolbar cleaner, start it and uninstall it in the usual way.

  5. Kay :-) said on May 25, 2014 at 2:35 am

    I just want to thank you for the helpful information. EVERYTHING to fix this problem I’ve been trying to remedy is right here. Thank you so, so much for taking the time to share your knowledge with us and in essence really de-complicating our lives!! The follow-up comments were fantastic, too!!

    Hugs all around, everyone, even if you don’t want ’em, I’m coming for ya ;). Hugs!!

  6. EVI said on May 16, 2014 at 1:27 pm


  7. wut said on April 29, 2014 at 10:20 am

    Avast’s “Online Security” is an absolute piece of GARBAGE. It borders on MALWARE. It slowed down the browser access on Firefox and IE so much that it made them both unusable! After I removed this P.O.S. “online security” malware, browsing on both browsers were perfectly smooth.

    Craptastic crap. When installing Avast, use custom settings and DO NOT install “online security”.

  8. cantstandbuffering said on April 17, 2014 at 8:54 pm

    Thanks for the instructions to remove avast permanently. Hopefully it will fix the buffering problem on Twitch. I will keep you guys updated.

  9. Uhtred said on March 18, 2014 at 5:59 pm

    Probably obvious, but sometimes obvious is overlooked… If you disable the AVAST self protection module, don’t forget to re-enable afterwards.

  10. b003 said on March 18, 2014 at 4:39 am

    Ugh reminds me of my “conduit” experience.

  11. insanelyapple said on March 17, 2014 at 2:17 pm

    Avast is getting into same wagon as other companies in my opinion; they changed privacy policy to collect meta data while scanning files – of course they’re claiming it’s safe, there’s no way to identify each person because it’s anonymous process…But nowadays, there’s always a way, soon or later it turns out that meta was requested by gov’t – mostly american. I’ve lost trust to them.

  12. Steve said on March 17, 2014 at 12:12 pm

    Alternatively you can go into avast’s settings and remove the extension from Firefox,chrome and ie.

  13. Nebulus said on March 17, 2014 at 10:33 am

    Or even better, don’t install that extension in the first place by choosing “Custom” during Avast! installation and then selecting only the components you really want.

    1. Martin Brinkmann said on March 17, 2014 at 11:09 am

      Good point. Then again, most users probably do not use that option.

  14. Jaroslav Matura said on March 17, 2014 at 10:02 am

    I am not entirely sure if I am speaking truth right now, but you can also go to Programs and Features, click Uninstall/repair avast!, and uncheck Browser protection (or something) in the installation dialog.

    1. Martin Brinkmann said on March 17, 2014 at 11:10 am

      You are right. If you select to uninstall, and the change on the windows that pops up, you can remove the Browser Protection module under Tools there.

      1. MrsSassy said on September 27, 2016 at 8:42 am

        Alrighty then! I just BOUGHT Avast 2 days and installed it after Firefox was causing my computer to shut down my screen forcing me to unplug it to regain use of it again!
        Now what? since I have the paid version of Avast and subscribed for 3 computers for 3 years argggg

        I was using AVG ( paid version without any issues for over 28 years now ) but I suspected a virus so knee jerk reaction was to uninstall it and buy a new Anti virus/Internet security program and now I discover it may have been AVAST causing the problem?

        I never did find any malware nor Virus and so far my computer has been working fine.
        ( added to mention… I am experiencing delays at this site now ) but everything has been working fine other wise but I haven’t gone globe trotting online yet…)

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