Couldn’t load XPCOM on Firefox in Windows 10

Milan Stanojevic
by Milan Stanojevic
Deputy Editor
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  • Users have reported issues when trying to load XPCOM on Mozilla Firefox.
  • The article below will show you exactly what needs to be done if that happens to you too.
  • To learn more about Mozilla Firefox, check out our dedicated Firefox page.
  • We also have a dedicated Browsers page filled with info on all major web browsers.
Couldn’t load XPCOM firefox

Problems with certain applications will occur sooner or later, therefore it’s important to know how to fix those problems. Users reported Couldn’t load XPCOM error while trying to start certain applications on Windows 10, so let’s see if we can fix this problem.

The solutions listed below will also prove useful if you are encountering the following issues:

  • Couldn’t load XPCOM
  • Firefox couldn’t load XPCOM
  • Couldn’t load XPCOM Windows 10
  • Firefox couldn’t load XPCOM Windows 10

How do I fix XPCOM loading errors?

1. Consider using another browser

If Firefox is giving you a hard time in general, and not just because of the XPCOM issues, then maybe you should consider using a different browser entirely.

On that note, we recommend you give Opera a shot. This web browser is built using the Chromium engine, just like Edge and Chrome, and it is extremely stable and reliable, allowing for near-zero errors to occur.

It also has some extra tools that most other browsers don’t except through the use of extensions, such as a built-in VPN, and a very efficient ad-blocker.



Enjoy an error-free browser that is incredibly fast and also has a high level of customization at no cost at all.

2. Completely remove Firefox and reinstall it

Users reported that this error occurs when they try to open Firefox and that they are unable to use Firefox at all. This can be a major problem if you use Firefox as your default web browser, but you should be able to fix this problem simply by reinstalling Firefox.

To do that, first you need to uninstall Firefox application from your PC. Uninstalling Firefox isn’t usually enough, and to fix this problem you’ll have to completely remove all files associated with Firefox.

To do that, remove these folders:

  • C:\Program Files\Mozilla Firefox
    • If you’re using a 32-bit version of Windows 10
  • C:\Program Files(x86)\Mozilla Firefox
    • If you’re using 64-bit version of Windows.

Users are also suggesting to remove the following folders from your PC:

  • C:\Users\your_user_name\AppData\Local\MozillaFirefox
  • C:\Users\your_user_name\AppData\Local\Mozillaupdates
  • C:\Users\your_user_name\AppData\Local\VirtualStore\Program Files\Mozilla Firefox

After uninstalling Firefox and removing its installation directory, download the latest version of Firefox and install it. When the installation process is finished, start Firefox and check if the problem is resolved.

Few users reported that they were unable to remove Firefox from their PC unless they were using Windows 10 in Safe Mode. To enter Safe Mode, follow these steps:

  1. Hold the Shift key and click the Restart button. Alternatively, you can just manually restart your PC few times during the boot sequence.
  2. Select Troubleshoot > Advanced options > System Startup and click Restart.
  3. When your computer restarts, you’ll be presented with the list of options. Press the appropriate key to choose any version of Safe Mode.
  4. After entering Safe Mode, try to uninstall Firefox again.

If you don’t want to use Safe Mode to uninstall Firefox, you can also use tools such as REVO uninstaller to completely remove Firefox from your PC.

Editor’s Note: This article continues on the next page. If you’re interested in other Firefox posts, check out our wide collection of guides.