* 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: Reset Firefox Settings to Default (Refresh Firefox).

– If after disabling all plugins, the XPCOM error persists then reset Firefox to Default Settings by applying the steps in next Method.

When you find out which Firefox extension causes the problem, then remove it completely (by starting Firefox in Safe mode).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.To disable a Firefox plugin, from the main menu choose Add-ons 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. If Firefox starts without the XPCOM error message, then probably a Firefox extension (add-on) causes the 'Couldn't load XPCOM' error. Hold down the SHIFT key and then double click to open the Firefox application.Ģ.Start Firefox in Safe Mode by following this procedure: Start Firefox in Safe Mode and Disable Firefox's Extensions (Add-ons).ġ. * Note: Do not uninstall Firefox, just run the Firefox Installer and follow the on-screen prompts to repair/upgrade the current Firefox application. Internet Explorer, Chrome) download and Install the latest version of Firefox on your system. Reinstall – Upgrade Firefox to the latest version.ġ. 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). How to FIX the 'Couldn't load XPCOM' error in FIREFOX (Windows – All Versions). This guide contains instructions to resolve the 'Couldn't load XPCOM' error on Mozilla Firefox browser. Firefox's profile folder corruption may happen after a virus attack or after installing a third party extension on your Firefox browser. 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 XPCOM error description: Firefox couldn't open and the following error is displayed on screen: 'Couldn't load XPCOM'.

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