• Serious problem with Firefox


    After the new update of Firefox (76.0.1 I think) I’m having serious problems with it. Now it’s so sluggish that makes surfing virtually impossible. Especially in sites such as YouTube it stuck into a limbo and does absolutely nothing, so I can’t even watch a video without those problems. Because of that, the only way to close Firefox is by forcing it from Task Manager.

    Later I made a safe restart, which means deactivating the addons. No problems this time, everything runs smoothly. Nothing strange happens in safe mode. But when I try to open it in normal mode, this happens…


    Not only it doesn’t open at all, but it devours my memory by doing absolutely nothing! What’s going on here? Am I the only one with this problem recently? Why Firefox sucks so bad?

    I miss Windows XP...

    Viewing 10 reply threads
    • #2271022

      I’m running FF 77.0.1 – not having those problems.
      I would suggest you disable your add-ons and then enable them one by one to see which one is causing the slowdown.

      3 users thanked author for this post.
    • #2271025

      May also want to run a virus / malware scan on your machine

      1 user thanked author for this post.
    • #2271027

      @Terring, are you still on Windows 10 1809 or have you recently updated to 2004?
      you could try this in the about config of firefox:

      Lower Memory Usage When Minimized:
      If the preference name does not exist, it needs to be created.
      Right-click on the background and select “New -> Boolean.”
      Enter the name when prompted: config.trim_on_minimize set to TRUE

      when the browser is minimised, this frees up some firefox memory hogging.

      No problem can be solved from the same level of consciousness that created IT- AE
      • This reply was modified 3 years, 3 months ago by Microfix.
    • #2271102

      Like @PKCano, I have no such trouble with 77.0.1, and I didn’t with 76.0.1, either.

      I find it interesting that the screen shot shows Disk pegged at 100%. Is Firefox only sluggish when that’s the case, or also when Disk isn’t maxed? Is Firefox’s 2.9MB/s the greatest usage, or is there something else using even more?

    • #2271120

      Yes, I still have 1809 and I’ll stick to it until they fix the profile problem and stop pushing 1909 users to 2004. Now I tried to open Firefox in safe mode to disable addons, and guess what. Now it doesn’t open at all!


      The only solution I can think of right now is to reinstall it. I’ll check for malware though, just to be sure.

      I miss Windows XP...

    • #2271125

      Normally when you look in Task Manager (or similar) you will see several instances of Firefox.exe.  This is because recent versions of Firefox use something called “multi-process”, so could it be that you have this disabled?  Here’s a site which will talk you through it:


      Windows 10 Pro 64 bit 20H2

      1 user thanked author for this post.
    • #2271115

      If your disk stays busy all of the time, exhibits too much activity during idle time, sluggish response times, the Sysmain (1809) or Superfetch (some other windows versions) service can erratically cause most excess disk activity.

    • #2271140

      I know about the multi-process and I have no reasons to touch it at all, let alone knowing how do to it. Anyway, I decided to nuke Firefox and rebuild it. No problems right now, so far so good. I just wish I hadn’t had to do this.

      I miss Windows XP...

      1 user thanked author for this post.
    • #2271247

      Terring, did you install the newest flash update? It effects FF even though I have disabled Flash.

      Have you increased your virtual memory for Win 10? I did it the other day (better late than never) using the instructions here. It made a significant difference in the amount of memory that FF, and other applications, use. Then, again, I don’t usually have more than two or three tabs open at any time

      I use FF ESR because of several issues I had with the other version of FF. I’m now on FF ESR 68.9. The ESR version has always worked well for me. Know that it’s not updated as much as the other version of FF.

      I’m not a computer “geek” but I do read about computer issues when problems arise. So, take my suggestions for what they’re worth.

      1 user thanked author for this post.
      • #2271276

        I have been using Firefox ESR for years and never encountered anything untoward regarding performance or memory leaks/ hogging. One thing I prefer with ESR over the standard Firefox is, less junk that serves me no use/purpose. ESR gets no additional mozilla junkware during updates, I like to think of ESR as askwoody’s patching ‘Group B’ for browers receiving ‘security only’ updates.

        No problem can be solved from the same level of consciousness that created IT- AE
        4 users thanked author for this post.
        • #2271778

          Terring, did you know that Firefox has it’s own task manager that allows you to see which tabs or apps are slowing down your browser? If not, click here for more information on how to access it.


          2 users thanked author for this post.
          • #2271792

            CAS – is there a way to bring the FF Task Manager icon on to the icon bar?  I can’t see the possibility in the unused icons in the Customise screen.

            Dell E5570 Latitude, Intel Core i5 6440@2.60 GHz, 8.00 GB - Win 10 Pro

            • #2271800

              John, I don’t think there’s an icon for the task manager (FTM), but it’s easy enough to access when you need it. It won’t copy so you can paste it. And, I didn’t find anything about an icon in a search. Then, again, I only use duck duck go, metager and swiss cows as my search engines.

              I found another article about the FTM. Click here for more info.



              • This reply was modified 3 years, 3 months ago by CAS.
            • #2271861

              You can add a bookmark to the Bookmarks Toolbar if you want quick 1-click access.

              1 user thanked author for this post.
            • #2271996

              Thanks, SB9K. I never thought of that solution. Bookmark created.


              1 user thanked author for this post.
    • #2271612

      Have you tried renaming the sessionstore.js file in your profile directory (%UserProfile%\AppData\Roaming\Mozilla\Firefox\Profiles) or manually clearing the cache (%UserProfile%\AppData\Local\Mozilla\Firefox\Profiles)?

    • #2272002

      See the what’s new in Firefox 77.0.1.

      Fixed –
          Disabled automatic selection of DNS over HTTPS providers during a test to enable wider deployment in a more controlled way (bug 1642723)



      Windows 10 Pro 22H2

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