Browser extension is missing Firefox 74

Hello, after installing f secure on my PC the browser extension is missing (Firefox 74.0), even when I selected the setting "reinstall the extension" nothing happens.

Best Answers

  • UkkoUkko Posts: 2,974 Superuser
    Accepted Answer


    Sorry for my reply. I am only an F-Secure user (their home solutions).

    Sounds that maybe this trouble is known and fixed with one of recent Beta builds (last week):


    Enabling Firefox add-on fails on fs protection (PBL-6230)

    Perhaps, it should be soon available for stable installations (if trouble is not pinned to something that is not possible to update smoothly; if so - maybe can be with some delay).

    However, maybe topic subject is about completely another trouble. Actually, it is possible to contact their Official Support channels (for example, chat) and to ask about:



  • CaleCale Posts: 68 F-Secure Product Manager
    Accepted Answer


    We are in the midst of fixing this, but it will take some time to make a new product release. In the mean time, you can install the Firefox extension manually from here:

    What happened was that Firefox removed 'sideloading' support in version 74, which we were using to install the extension automatically. From now on the extension has to be installed manually. The extension itself works just fine in version 74.




  • bryan441bryan441 Posts: 38

    I am not sure but you may try this-

    Completely uninstall Firefox from your PC after that restart PC. Now install Firefox again and add the extension.

    Bryan Anderson

  • Subtle_SecretsSubtle_Secrets Posts: 1
    edited March 13

    I just installed F-Secure Safe this evening, and I also cannot get the program to install the browser extension into Firefox 74. I have clicked the button in F-Secure settings ---> "reinstall extensions" but the extension did not install. I have tried rebooting the computer, and then clicking "reinstall extensions" and still the extension does not show up in the Firefox extensions menu.

    Also, I have tried uninstalling Firefox in "Apps and Features", rebooting the computer, then re-installing Firefox, then clicking "reinstall extensions", but still no success.

    The F-Secure extension for Chrome and Edge (Chromium version) installed with no trouble.

    I am using Windows 10, version 1909

    All of this being said, this is not an urgent matter for me as I use Chrome for pretty much all of my browsing.

    Edit (March 13th): I've switched to a different AV at the moment, so I won't be much help troubleshooting the issue.

  • mZerOoOmZerOoO Posts: 3

    After installing Firefox 73.0.1 the add-on is working fine, so F-secure is not compatible with firefox 74, please fix this

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