Fix: “Couldn’t load XPCOM” on Windows 10

By: Milan Stanojevic
4 minute read

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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.

“Couldn’t load XPCOM” error on Windows 10, how to fix it?

Fix – “Couldn’t load XPCOM” 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 Files\Mozilla 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:\Users\your_user_name\AppData\Local\Mozilla\Firefox
  • C:\Users\your_user_name\AppData\Local\Mozilla\updates
  • 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.

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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

Sometimes your default Firefox profile might be corrupted and that can cause this error to appear. To fix this problem, you just need to create a new Firefox profile by following these steps:

  1. Press Windows Key + R and enter firefox.exe -p. Press Enter or click OK.
    couldnt-load-xpcom-firefox-profile-1
  2. Click the Create Profile button.
    couldnt-load-xpcom-firefox-profile-2

  3. For various PC problems, we recommend this tool.

    This software will repair common computer errors, protect you from file loss, malware, hardware failure and optimize your PC for maximum performance. Fix PC issues now in 3 easy steps:

    1. Download this PC Repair Tool rated "Excellent" on TrustPilot.com.
    2. Click “Start Scan” to find Windows issues that could be causing PC problems.
    3. Click “Repair All” to fix all issues with Patended Technologies (requires upgrade).

  4. Click Next.
  5. Enter the name of your new profile and click Finish. If you want, you can also set the storage directory for this profile.
    couldnt-load-xpcom-firefox-profile-3
  6. Select the profile that you just created and click Start Firefox button.
    couldnt-load-xpcom-firefox-profile-4

After creating a new profile you just need to check if this problem is resolved. If everything works without a problem, just keep using your new Firefox profile and everything should be in order. Some users are also suggesting to remove your Firefox profile completely and then create a new one, so you might want to try that as well.

Solution 3 – Delete everything from Temp folder and disable your antivirus program

Users reported that your Temp folder can sometimes interfere with Firefox and cause Couldn’t load XPCOM error to appear. To fix this problem you’ll have to delete all files from the Temp folder by following these steps:

  1. Press Windows Key + R and enter %temp%. Press Enter or click OK.
    couldnt-load-xpcom-temp-1
  2. Temp folder will now open. Select all files from the Temp folder and delete them.

If deleting files from the Temp folder doesn’t solve the issue, we suggest that you try disabling your antivirus software. Antivirus can sometimes interfere with certain applications and cause this and many other errors to appear, therefore be sure to disable it and check if that solves the problem. If disabling the antivirus doesn’t fix the problem, you might want to temporarily remove it and check if that solves this error.

Fix – “Couldn’t load XPCOM” Tor

Solution – Add Tor folder to the exclusions list

According to users, this error appears if you’re using Tor along with Malwarebytes, and in order to fix this problem, you need to add entire Tor installation directory to the list of exclusions in Malwarebytes. After doing that, you need to disable Malwarebytes and reinstall Tor completely.

Couldn’t load XPCOM error usually appears while starting Firefox, but in most cases this problem can be fixed simply by reinstalling Firefox. If that doesn’t work, feel free to try any other solution from this article.

READ ALSO:

For various PC problems, we recommend this tool.

This software will repair common computer errors, protect you from file loss, malware, hardware failure and optimize your PC for maximum performance. Fix PC issues now in 3 easy steps:

  1. Download this PC Repair Tool rated "Excellent" on TrustPilot.com.
  2. Click “Start Scan” to find Windows issues that could be causing PC problems.
  3. Click “Repair All” to fix all issues with Patended Technologies (requires upgrade).

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