Couldn’t load XPCOM – How to Fix Mozilla Firefox Error

In Short: Firefox Couldn’t load XPCOM is a general issue you may face while opening it on your Windows laptop or PC, this article covers the ways to fix it.

Mozilla Firefox is one of the popular browsers after Google Chrome, it is a favorite browser for web developers as it has many extensions to support development, Mozilla releases their updates for Firefox as it gets newer features, sometimes it becomes incompatible with windows due to new features or due to other installed programs, even after lots of testing it fails to be compatible with windows and related programs.

Sometimes it acts weird and gives you errors one of them is “Couldn’t Load XPCOM” while launching Firefox on Windows computers. If you tried fixing it by doing the virus scan, removing junk files, and doing system reboot many times, but it does not fix this error then here are few recommended methods to fix Couldn’t Load XPCOM error.

Ways  to Fix Firefox Couldn’t Load XPCOM error

Method 1.  Close Couldn’t load XPCOM error message, open another browser like Internet Explorer or Google Chrome Download the latest version of Mozilla Firefox and upgrade to a newer version.
upgrade firefox

After the complete upgrade, you may be able to run Firefox as usual.

Method 2: Complete Uninstall and Re-install of Firefox

Method 1 may not work for everyone because upgrading to the new version may not remove the root cause of this problem. If the above method works then great, if not you need to completely uninstall Firefox and re-install to the newest version in order to get this problem fixed.

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

  • Uninstalling Firefox
  • Remove Registry entries
  • Remove from Program files
  • Delete entries from AppData folder
  • Deleting from Program data Folder

All above task is going to tedious, especially removing entries from the registry, since I don’t recommend playing with Registry Editor, deleting the wrong registry keys may lead to other errors or complete system failure.

So Download and install Iobit Uninstaller and uninstall Firefox using Uninstaller, also perform Powerful Scan which finds all registry entries and leftovers of Firefox, select all leftover items and delete them.

couldn't load xpcom
Uninstall Firefox

After Uninstalling Firefox by Iobit Uninstaller, you need to delete one more folder from AppData.

Press the Win+R button it will open the Run dialog box, type %appdata%  in it, and hit enter.



It will open the Roaming folder find and delete the Mozilla folder.

mozilla roaming folder

Firefox is now completely removed from your computer, now Download the Latest version of Firefox using another browser and install it, you would be able to open and browse the internet on Firefox without any error.

Watch this Video Tutorial

Play the above video to watch the complete Uninstall and Re-install of Firefox. If you face any issue during this process please comment below.

This error is more likely to cause by some kind of malware that messes with Mozilla Firefox, it is recommended to Scan your computer for possible malware using any good Antivirus program like Kaspersky Total Security

Or download one of the best free antiviruses and perform the system scan.

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