Couldn’t load XPCOM, this is how to fix it

There are many causes of “Couldn’t load XPCOM” error on Firefox. The cause may be either after updating Windows or by the Firefox profile folder crashed. The Firefox profile folder is faulty due to virus attack or after installing the 3rd extension on Firefox.

So how to fix the “Could not load XPCOM” error in Firefox, please refer to the article.

1. Reinstall or upgrade the latest version of Firefox

1. Use another browser (such as Chrome browser, Internet Explorer, …) to download the latest version of Firefox on the system and install.


Do not uninstall Firefox, just run Firefox Installer and follow the on-screen instructions to fix / upgrade your current version of Firefox.

2. Open Firefox in Safe Mode and disable Firefox add-ons

1. To open Firefox in Safe Mode, follow these steps:

– Long press Shift and then double-click to open Firefox.

– Select Start in Safe Mode.

2. If you open Firefox without displaying XPCOM error messages, the cause of the error is probably due to an add-on installed on Firefox.

In this case you can disable each add-on installed on your browser, then start Firfox in normal mode to find which plugin causes the problem.

To disable the plugin on Firefox, click the 3 dash icon in the top right corner of the screen, select Add-ons.

On the Extensions window, disable the installed add-ons (disable each add-on), then restart Firefox in normal mode and find the extension. is the cause of XPCOM error.

When the extension is found to be the cause of the error, the next step is to completely remove the extension (by opening Firefox in Safe Mode).

If the error persists, the next solution is to reset Firefox to its original default setting.

3. Reset your Firefox browser to its default settings

1. Open Firefox in Safe Mode.

2. On the popup screen, select Refresh Firefox.

3. Select Refresh Firefox again.


Refresh Firefox will restore all browser settings to their original default state by creating a new user profile and removing all add-ons in the Firefox browser, plugin, and search engine. However, some items will not be deleted, including:

  • Bookmarks.
  • Browsing history.
  • Password.
  • Cookies.
  • Personal dictionary.
  • Automatically enter information.
  • Open tabs and windows.

4. Uninstall and then reinstall Firefox on your system

If you have applied the above solutions and still do not fix the error, you can try the solution is to uninstall then proceed to reinstall Firefox on the system.

  1. Backup all passwords, bookmarks, settings, … on Firefox.
  2. Completely uninstall Firefox and the folders on your computer.
  3. Install the latest version of Firefox.
  4. Restore the settings on your Firefox browser.