Firefox XPCOM error Couldn't load XPCOM (Solved)
Firefox XPCOM error description: Firefox couldn't open and the following error is displayed on screen: "Couldn't load XPCOM". The XPCOM error, may caused on a Windows based computer whenever a user tries to open Mozilla Firefox after a Windows Update or if the Firefox's profile folder is corrupted. Firefox's profile folder corruption may happen after a virus attack or after installing a third party extension on your Firefox browser.
This guide contains instructions to resolve the "Couldn't load XPCOM" error on Mozilla Firefox browser.
How to FIX the "Couldn't load XPCOM" error in FIREFOX (Windows – All Versions).
Important: Before applying the instructions bellow to resolve the XPCOM Firefox problem, make sure that your computer is virus/malware free by following the steps in guide: How To Scan Your Computer for Viruses and other Malicious Programs (Malware Removal Guide).
Method 1. Reinstall – Upgrade Firefox to the latest version.
1. From another Web browser (e.g. Internet Explorer, Chrome) download and Install the latest version of Firefox on your system. *
* Note: Do not uninstall Firefox, just run the Firefox Installer and follow the on-screen prompts to repair/upgrade the current Firefox application.
Method 2. Start Firefox in Safe Mode and Disable Firefox's Extensions (Add-ons).
1. Start Firefox in Safe Mode by following this procedure:
- Hold down the SHIFT key and then double click to open the Firefox application.
- Choose Start in Safe Mode
2. If Firefox starts without the XPCOM error message, then probably a Firefox extension (add-on) causes the "Couldn't load XPCOM" error. At this case, disable one-by-one the installed Add-ons and then close and start Firefox normally, until you find out which plugin causes the problem.
To disable a Firefox plugin, from the main menu choose Add-ons
- At 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.
- When you find out which Firefox extension causes the problem, then remove it completely (by starting Firefox in Safe mode).
– If after disabling all plugins, the XPCOM error persists then reset Firefox to Default Settings by applying the steps in next Method.
Method 3. Reset Firefox Settings to Default (Refresh Firefox).
1. Start Firefox in Safe Mode.
2. Choose Refresh Firefox.
3. Choose Refresh Firefox again. *
* Note: 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:
- Bookmarks
- Browsing history
- Passwords
- Open windows and tabs
- Cookies
- Web form auto-fill information
- Personal dictionary
Method 4. Uninstall and Re-install Firefox from your System.
Finally, if none of the above methods resolves the XPCOM error when starting Firefox, then:
1. Backup your Firefox Passwords, Bookmarks, Settings, etc.
2. Completely remove Firefox application and folders from your computer.
3. Install the latest Firefox version.
4. Restore your Firefox settings.
Method 5. Restore Your Computer To An Earlier Working State by using System Restore.
1. Try to restore your computer to a previous working state in order to resolve the XPCOM error in Firefox.
- How to Restore Windows 10, 8 or 8.1 to a previous working state
- How to Restore Windows 7 or Vista to a previous working state.
That’s all folks! Did it work for you?
Please leave a comment in the comment section below or even better: like and share this blog post in the social networks to help spread the word about this.
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Kristina
July 11, 2018 @ 10:10 am
I've already purchased AVG and don't want to pay twice to have it downloaded.
Please.
It's on my file under my email.
Thanks
Krissy
Lakonst2013
July 11, 2018 @ 1:28 pm
@Kristina: Use another browser (e.g. Chrome or Internet Explorer) to access your email and to get the "Activation Code" for the AVG.
Karlene P. Grinnell
November 4, 2018 @ 8:47 pm
Instead of trying to "REPAIR" Firefox, CAN I DOWNLOAD CHROME…WITHOUT first removing / doing anything with FIREFOX?
Lakonst2013
November 5, 2018 @ 11:20 am
@Karlene P. Grinnell: Of course
David Kit Friedman
December 5, 2018 @ 9:15 am
Method 1 of reinstalling worked fine for me.
Julian Opificius
May 8, 2019 @ 3:49 am
Methods 1-4 didn't work for me, but after step 4 I discovered that the program started OK when double-clicking the icon on the screen (without resorting to safe mode) but NOT by clicking once on the icon on quick-start bar – strange. I deleted the icon on the quick-start bar, restarted FF from the icon on the main window – allowing the icon on the quick-start bar to reestablish itself, and everything is now back to normal.
BF7
July 13, 2019 @ 1:13 am
With the new version of Firefox (68.0) upgrading doesn't work because it won't share data with older versions due to tighter security protocols. So what do you do, I had lots of extensions and xpcom also prevented Firefox from loading in safe mode?
What did was to save the relevant C:\Users\%username%\AppData\Roaming\Mozilla\Firefox\Profiles\ folder as backup (I didn't need it). Uninstall any versions of Firefox you have on your pc using the standard Microsoft uninstaller. Download the previous version (67.0.4) and install it. I unchecked the mozilla maintenace option to limit its capacity to upgrade in the background. It picked up the data from corrupted installation and everything is now back and working.
If it doesn't work try downloading at the installing the 32 or 64 bit version instead.
Dash
February 19, 2020 @ 6:08 am
Thanks! Problem fixed with easy-clear instructions
Tom Wayburn
May 24, 2020 @ 7:25 am
I paid for another year of Vipre; but, due to a non-standard distribution of software and data on my three internal drives, I ended up without a working copy of Vipre. I downloaded the free version of Malwarebytes, which found 178 PUPs or worse. By the time, I had solved my virus problem, Firefox was no longer in evidence. I do not recall uninstalling it. In any case, with no further changes, the XPCOM problem was solved. I will reinstall Firefox (67.0.4) when time permits. Thanks to all.
AMeSh
May 14, 2021 @ 5:53 am
After updating the portable version of Firefox, this message began to go out. In safe mode it does not start. Firefox disappointed unpleasantly. In the pit!