How to Troubleshoot Firefox When It Crashes

Misbehaving Firefox Featured

Is your Firefox browser stuttering, freezing, crashing, or eating up gigabytes of RAM? Here’s how to troubleshoot Firefox when issues start showing up.

Start by making sure you’ve also checked out our past suggestions about how to solve problems with Firefox. If those solutions didn’t work, then read on.

The Better Way to Find a Problematic Add-On

The first thing to do when Firefox starts misbehaving is to check your installed add-ons to see if any one of them is the culprit. Don’t go disabling them one by one, though, as that could end up taking up a significant chunk of your time, depending on your number of installed add-ons.

You can find the problematic add-on more quickly if you disable them in batches and apply a little trick where you split them into subgroups. Let’s check out how to do that.

Misbehaving Firefox About Addons

Select “Add-Ons” from Firefox’s primary menu or type about:add-ons in the URL bar and press Enter to see the browser’s add-on management page. Click on the “Extensions” entry of the menu on the left,to see a list of all your installed add-ons.

Misbehaving Firefox Disable Addons

Instead of disabling your add-ons one by one, it’s better to disable half of them. Then, restart your browser and try to replicate the problem you had previously. If the problem rears its ugly head again, that means that the problematic add-on remains active. If it doesn’t, the culprit was one of the add-ons you disabled. Swap groups by re-enabling half of the disabled ones and repeat.

This approach, dealing with your add-ons in groups, makes it much easier to pinpoint the add-on you should disable. By finding out, in one single step, if the problem lies in one half of your extensions, you won’t have to check the other half. This will end up saving you significant time and make the troubleshooting process much more manageable.

Get Information from the “About” Pages

Although the most probable cause of problems in the majority of Firefox installations is some misbehaving add-on, that’s not always the case. And even if it is, you might want more information about it.

Thankfully, Firefox provides abundant information about the way it performs as well as some extra options.

Note: to access any of them, input them precisely as you see them here in the browser’s URL line and press Enter on your keyboard.


This allows you to check how much storage space Firefox eats up in your RAM, SSDs and hard disk drives.

Misbehaving Firefox Cache


Although in our screenshot you see that “No crash reports have been submitted,” that’s because we used a brand-new Firefox installation for this tutorial. It’s almost a given that when using this code you will see a bunch of submitted (to Mozilla, Firefox’s developers) and pending crash reports related to any problems the browser met – trivial or significant.

Misbehaving Firefox Crashes


One of the most useful “about” pages for troubleshooting Firefox, “about:memory” allows you to check the browser’s memory usage.

Misbehaving Firefox Memory

Click on “Measure” in the “Show memory reports” section to check out specifically what eats up memory and how much.

If you turn your attention to the “Free memory” section, the three available options allow you to minimize Firefox’s memory usage in three different ways.

  • The “GC” button performs a global garbage collection, eliminating any “leftovers” from past browsing, usually from JavaScript code included in pages.
  • The “CC” button does a “Cycle Collection” that does the same but cleans unnecessary fluff from Firefox itself.
  • Finally, the “Minimize memory usage” button does what the other two do but “runs” each cleanup three times, plus some others on top, to offer a simple way to do exactly what its name states: “minimize memory usage.”


To get more information about anything Firefox has connected to, visit the “about:networking” page. On this page you will find pages you’ve actively visited as well as network locations you browser or your add-ons can connect to. Thus, although some of those might seem useless, or even suspicious, that’s not (always) the case.

Misbehaving Firefox Networking


Probably one of the most important “about pages” when troubleshooting Firefox, “about:performance” shows the usage of resources by individual tabs/pages, as well as add-ons. You can check them out in real time by turning your attention to the “Energy Impact” column.

Misbehaving Firefox Performance


If nothing works, the last step before reinstalling Firefox is checking if your profile has been corrupted. Although there is no easy way to do this, you can try visiting “about:profiles” and creating a new one by clicking on the “Create a New Profile” button. Restart Firefox by clicking on the “Restart normally …” button and use it for a while to check if everything works.

Misbehaving Firefox Profiles

If it’s still not working right, the ultimate solution is reinstalling the browser from scratch. Before that, and especially if you’re using Linux (when something like this is much easier than when you’re using Windows), it’s worth it to update everything else in your system (meaning both the operating system and any installed applications) to eliminate the much rarer possibility of software conflicts.

In addition to the above “about” pages, the “about:config” is the most important one and contains many options for you to improve your Firefox performance.

Odysseas Kourafalos
Odysseas Kourafalos

OK's real life started at around 10, when he got his first computer - a Commodore 128. Since then, he's been melting keycaps by typing 24/7, trying to spread The Word Of Tech to anyone interested enough to listen. Or, rather, read.

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