Couldn’t load XPCOM: Here’s how to fix this error for good


Milan Stanojevic
by Milan Stanojevic
Deputy Editor
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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.

How to fix XPCOM loading errors

Fix – Couldn’t load XPCOM on Firefox

Solution 1 – 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 C:Program FilesMozilla Firefox folder if you’re using a 32-bit version of Windows 10 or C:Program Files (x86)Mozilla Firefox folder if you’re using 64-bit version of Windows. Users are also suggesting to remove the following folders from your PC:

  • C:Usersyour_user_nameAppDataLocalMozillaFirefox
  • C:Usersyour_user_nameAppDataLocalMozillaupdates
  • C:Usersyour_user_nameAppDataLocalVirtualStoreProgram FilesMozilla 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.

Solution 2 – Create a new Firefox profile

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.