How Can I Fix Couldn't Load XPCOM Error in Firefox

Mozilla Firefox is the most common and sought after web browser after Google Chrome. It’s a special favorite amid web developers as well owing to its vivid extensions supporting and engendering web development. Mozilla releases its web browser updates periodically and sometimes after upgrading it becomes incompatible with the operating systems crediting to its newly added features or due to some pre-installed programs. The most recurring error message that springs up in such situation is Couldn’t load XPCOM.

If you tried fixing this error by running various virus scans, removing junk files by clearing the cache and performing system reboot recursively; you'd have noticed that none of this fixes the error.


But every problem does have a solution. In this article, you will get the causes of the error generated and some of the methods we recommend to fix couldn't load XPCOM error. Every Operating system may have a different solution to the problem and they have been listed here. Give it a try before any expert intervention.

Causes Of Firefox XPCOM Error

The XPCOM error may occur because of the following possibilities:

  1. It may occur on a Windows O.S based computer after the windows is updated and the user tries to open Firefox subsequently.
  2. If the Firefox’s profile folder is corrupted. Firefox’s profile folder corruption usually happens following a virus attack or after installing a third party extension on the Firefox browser.

How To Fix Couldn't Load XPCOM Error

Let's dig into the methods to fix this error. We have listed various methods to Couldn't load XPCOM error in Windows, Linux, Ubuntu, etc.


Fix Couldn't Load XPCOM Error In Linux

The initial problem encountered upon updating Firefox is

To solve this error in Arch Linux follow these steps:


This will solve the problem of XPCOM error.

Fix Firefox Couldn't Load XPCOM Error In ThunderBird

Thunderbird program and Thunderbird Profile folders are not stored in same place.

So you can uninstall Thunderbird and then reinstall a fresh version without any adverse effects on emails and downloads etc.

To uninstall follow these steps:

Step 1: Go To Start.

Step 2: Select Setings.

Step 3: Go To control Panel.

Step 4: Choose 'Programs and Features'.

Step 5: Select Mozilla thunderbird and click on uninstall.

To install, download from here- Download ThunderBird

Couldn't Load Xpcom Error In Tor Bundle Browser

If the XPCOM error appears when you open the Tor Browser Bundle , it is because webroot security software was preventing tor from initiating.

Though you don't have to delete your webroot security package. Just follow these simple steps:

Step 1: Open Webroot

Step 2: Click on "Identity Protection"

Step 3: Click on "Application Protection"

Step 4: Find the file that has the word "tor" in in c:\users\desktop\torbrowser\browser"

Step 5: Then on the right side you will see the following options: protect, allow, deny.

Step 6: Select "allow"

This will fix the XPCOM problem in Tor Bundle Browsers.

Fix Couldn't Load XPCOM Error In Windows

#Precationary Method:: Run An Anti-Virus Through Your System

The precautionary measure to ensure before resolving the XPCOM Firefox problem is to make sure that your computer is virus/malware free by following these steps:

Step 1: Boot Your Computer into Safe Mode

For Windows 7, Vista & XP:

1. Restart your computer and press the “F8” key before the windows logo appear

2.The “Advanced options” menu appears on the screen, steer to “Safe Mode With Networking” option  and press Enter.

For Windows 10, 8.1/8:

1. Use “Windows” + “R” keys to open the RUN window.

2.Type msconfig & select OK.

3.Go to the  Boot tab.

4.Select the Safe Boot & Network options and select OK.

5. Restart your computer.

Step 2. Run TDSSKiller Anti-rootkit utility.

1.Download Kaspersky’s TDSSKiller Anti-rootkit utility in your computer from here- TDSSKILLER.

2.Run TDDSSKiller.

3.Accept the license agreement.

4.Click Next.

5.Use the “Start Scan” button and wait until the scan is completed.

6.Finally select “Cure” to remove the infections (if found).

Step 3: Delete malicious entries from Windows Startup.

1. Download and install CCleaner from here-CCleaner Installation.

2. Run CCleaner utility.

3. Select “Tools”.

4. Click on the “Startup” button.

5. Choose the “Windows” tab.

6. Select and delete any suspicious entry that is listed there.

Step 4:Uninstall Unknown or Unwanted programs

1. Open Windows Control Panel.

2. From the program list, find and remove any unknown or unwanted application that is listed here.

Step 5: Reset your Firefox Browser Settings.

This step is optional and you must apply it, if the XPCOM error still reoccurs, in order to make sure that all unwanted plug-ins, extensions and settings were removed from browser when the above steps were performed.

Just follow these quick steps:

1. From Firefox’s menu icon choose Help.

2.Select Troubleshooting Information. the Refresh Firefox button.

4.Select Reset Firefox again.

5.Close all open Firefox windows.

If the XPCOM error persists imply any of the methods enlisted below for an error ridden Firefox browsing experience.

FIX Couldn't Load XPCOM Step by Step Guide

Here are some more methods to help you get rid of this error.

METHOD 1: Reinstall And Upgrade Firefox To The Latest Version

Using an alternative Web browser download and Install the latest version of Firefox.

You Do not have to uninstall Firefox, just run the Firefox Installer and follow the on-screen prompts to repair and upgrade the current Firefox application.

You can download the latest version from here: Firefox Download.

METHOD 2: Uninstall Firefox Completely And Re-install

Method 1 may not prove to be beneficial to all because upgrading to the new version may not remove the root cause of the error.

Complete Uninstall means you need to remove everything related to Firefox from your computer like –

  1. Uninstalling Firefox
  2. Remove Registry entries
  3. Remove from Program files
  4. Delete entries from AppData folder
  5. Deleting from Program data Folder.

It is not recommend tampering with the Registry Editor because deleting the wrong registry keys may lead to other errors or complete system failure.

Instead Download and install Iobit Uninstaller and uninstall Firefox using Uninstaller.

Step 1: Click on Uninstall Firefox

Step 2: After Uninstalling Firefox you need to delete one more folder from AppData.

Step 3: Press Win+R button it will open Run dialog box, type %appdata% and press enter.

Step 4: It will open Roaming folder find and delete Mozilla folder.

Firefox is now completely removed from your computer. Download the latest version of Firefox from here- Upgraded Version Of Firefox

METHOD 3: Start Firefox In Safe Mode And Disable Firefox’s Extensions (Add-ons)

Step 1: Hold down the SHIFT key and then double click to open the Firefox application.

Step 2: Choose Start in Safe Mode.

Step 3: If Firefox starts without the XPCOM error message, then maybe a Firefox add-on caused the error.

Step 4: At the Extensions pane, Disable the installed Add-ons, (one every time) and then restart Firefox normally until you find out which extension causes the XPCOM problem.

Step 5: Remove the Firefox extension causing the error.

METHOD 4: Reset Firefox Settings To Default (Refresh Firefox)

Step 1: Start Firefox in Safe Mode.

Step 2: Choose Refresh Firefox.

The refresh Firefox feature restores all browser settings to default, by creating a new user profile and by removing all Firefox’s Add-ons (extensions) and customization (preferences, plugins, added search engines). The Firefox Refresh doesn’t remove these items:

  2. Browsing history
  3. Passwords
  4. Open windows and tabs
  5. Cookies
  6. Web form auto-fill information
  7. Personal dictionary

All these methods are bound to give you an Error free browsing experience.  You can try all these methods by yourself without any tech support, so do try to fix the issue by yourself before turning to the tech-experts. But if nothing suits you and your Firefox browser still doesn’t work efficiently even after trying the above methods, and then try the Mozilla feedback and complaint forum for some expert guidance.

No posts to display