Having Firefox issues? Here’s how to fix them for good

Milan Stanojevic
by Milan Stanojevic
Windows & Software Expert
Milan has been enthusiastic about PCs ever since his childhood days, and this led him to take interest in all PC-related technologies. Before joining WindowsReport, he worked as a front-end web developer. Read more
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  • Mozilla Firefox is a great browser with millions of users worldwide.
  • Unfortunately, Firefox errors can sometimes appear, but you should be able to fix most of them.
  • Want to learn more about Firefox? Be sure to check our Firefox Hub, for more in-depth guides.
  • If you're interested in other web browsers, check them all out on our dedicated Browsers section.
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Firefox is known as one of the best browsers for the Windows platform, but unfortunately, it seems that Windows 10 users are having certain issues with it and now Firefox is not working for them.

Firefox is one of the most used web browsers in the world, and this application has been around for years.

How do I fix Firefox not working on Windows 10?

Firefox issues can be problematic, and prevent you from using your browser. As for issues, we’ve compiled a list of common problems that users reported with Firefox:

  • Firefox won’t open – This issue can occur if there’s a problem with your Firefox profile. To fix it, simply recreate the profile and check if that solves your issue.
  • Firefox too slow, using too much RAM – High RAM usage can occur due to your extensions, so be sure to disable all extensions that you don’t need and check if that helps.
  • Firefox high CPU usage – Sometimes high CPU usage can appear and cause issues with Firefox. This can be due to your antivirus, so be sure to disable it temporarily.
  • Firefox keeps crashing, freezing, not responding – Sometimes your configuration can cause problems with Firefox. However, you can fix that problem simply by starting Firefox in Safe Mode.

1. Disable problematic add-ons

  1. Open Firefox and click the Menu button in top right corner.
  2. Choose Add-ons from the list.
    Firefox too slow
  3. Click the Extensions tab on the left. A list of installed extensions should open.
  4. Now disable all extensions by clicking the Disable button.
    Firefox high CPU usage
  5. Restart Firefox and check if the issue is resolved.
  6. If the problem is fixed, you can try enabling extensions one by one until you find the one that is causing you problems.

According to some users, the add-on that caused the crash for them was FlashGet, but bear in mind that almost any add-on can cause Firefox to crash, so you might have to disable or remove certain add-ons in order to fix this issue.

If you can’t open Firefox at all, it’s always a good idea to run it from Safe Mode. To access Safe Mode do the following:

  1. Press the Start button, click the Power button, press and hold Shift on your keyboard and choose the Restart option.
  2. Once your computer restarts, choose Troubleshoot > Advanced options > Startup Settings and click the Restart button.
  3. After your computer restarts again press F5 to choose Safe Mode with Networking.
  4. When Safe Mode starts, try disabling any extensions from Firefox by following the steps above.

If Firefox works normally in Safe Mode, the issue is probably caused by some third-party program that you have installed, so you’ll have to find the problematic program and disable it in order to fix this problem.

2. Use a different browser

If you can’t seem to escape the fact that Firefox is not working on Windows 10 as it should, then we recommend switching to another browser. These days, you truly have options.

Let’s go with the one that makes the most sense: the Opera browser.

It is based on Chromium, so it will be compatible with all and any websites. It has been modified to include a lot of new and different functionalities.

Some of the best that we like are:

  • Workspaces: group a bunch of tabs together in a workspace to keep yourself better organized
  • Free VPN: a proxy-like VPN that is free and comes with unlimited bandwidth
  • Integrated Messenger: reach out and chat with friends on Facebook Messenger, WhatsApp and more without leaving the browsing or switching tabs

And many more just like this.



If for whatever reason you have issues with Mozilla Firefox, Opera is an excellent alternative to try.

3. Reinstall Firefox

If Firefox issues are interfering with your work, perhaps you should try reinstalling Firefox. Sometimes your installation can get corrupted, and that can cause various issues. However, you can fix that problem, simply by reinstalling Firefox.

There are several methods that you can use to reinstall Firefox, but the most effective one is to use uninstaller software.

In case you don’t know, uninstaller software such as IObit Uninstaller completely removes any application from your PC.

In addition, this software will also remove all files and registry entries associated with the application you want to remove ensuring that these files don’t interfere with your system.

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4. Start Firefox in Safe Mode

  1. Locate the Firefox shortcut on your desktop, hold the Shift key and double-click it.
  2. When the dialog box appears, click Start in Safe Mode button.
    Firefox won't open

After doing that, Firefox should start in Safe Mode. If the issue doesn’t appear in Safe Mode, it’s possible that one of your extensions or settings is causing this issue.

5. Check your antivirus

If you’re experiencing Firefox issues on your PC, the issue might be your antivirus software. Several users reported that HTTPS Scanning feature in Avast caused issues with Firefox, but you can fix this problem by doing the following:

  1. Open Avast from and choose Settings in the bottom left corner.
  2. Choose Components > Web Shield.
  3. Now click Customize button.
  4. Uncheck Enable HTTPS Scanning option and save changes.

If you’re using different antivirus software, you might want to try disabling this or other similar features in it. In case that doesn’t work, your next step would be to completely disable your antivirus software.

Several users reported that this wasn’t effective, and according to them, they managed to fix the issue by removing their antivirus altogether.

If removing the antivirus solves your problem, you should consider switching to a different antivirus solution. Which one? We recommend BullGuard, which offers multi-layered protection with the power from the cloud and machine learning.

6. Clear your cache

  1. Click the Menu button in the top right corner. Choose Library > History > Clear Recent History.
    Firefox won't open
  2. When Clear All History window opens, set Time range to clear to Everything. Expand the details section and check everything like on our screenshot. Now click Clear Now button.
    Firefox too slow

After doing that, the history should be cleared and the problem will be resolved.

7. Refresh Firefox

  1. Open Firefox.
  2. In the address bar enter about:support and click Refresh Firefox button.
    Firefox keeps crashing
  3. Now follow the instructions on the screen to refresh Firefox.

After you’re done, the Firefox should be restored to default and the problem will be permanently resolved.

8. Remove your Firefox profile

  1. Close Firefox.
  2. Now press Windows Key + R and enter firefox.exe -p. Press Enter or click OK.
  3. List of available profiles will appear. Select your user profile, it should probably be labeled as default and click the Delete Profile button.
    Firefox high CPU usage
  4. Now pick the desired option. If you want to completely remove your profile, click the Delete File button.
    Firefox keeps crashing

After doing that, your profile should be removed, and a new one will be created once you start Firefox. You can also create a new profile from this dialog box. To do so, follow these steps:

  1. Click the Create Profile button.
    Firefox won't open
  2. Click Next.
  3. Enter the desired name for your profile and click the Finish button.
    Firefox using too much RAM
Firefox high CPU usage

Now you just have to select the new profile and click the Start Firefox button.

After creating a new user profile, the issue should be completely resolved. Keep in mind that this method will remove your history, bookmarks, and saved passwords, so be sure to back them up beforehand.

9. Consider using Beta or Nightly version

If the Firefox issues are still present, you might be able to solve them simply by switching to the Beta or the Nightly version of Firefox. To do that, you just need to remove Firefox from your PC and then install the Beta version.

The Beta version has the latest updates, but since this version isn’t fully tested, some new issues might appear.

On the other hand, the Nightly version offers the latest updates, as soon as they are implemented, but since these updates aren’t fully tested, it’s possible that some issues might occur.

Firefox issues on Windows 10 can cause many problems, and in most cases, these problems are caused by a third-party application or a Firefox extension.

In order to fix Firefox issues, you just have to disable or uninstall the problematic app/extension.

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Frequently Asked Questions

  • To remove malware from Firefox, press Ctrl + Shift + A to open the extensions page. From there, remove all suspicious extensions that you don’t recognize or remember installing.

  • Yes, Firefox has a Phishing and Malware protection feature that will provide you basic protection against malicious websites.

  • To reset Firefox, click the Menu icon and choose Help > Troubleshooting Information. Now click on the Refresh Firefox button and follow the instructions on the screen.

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