Third-party Extensions on Firefox- The issue with the XPCOM may arise if there are third-party extensions installed on the Firefox app.
Corrupt Firefox User Profile- The User Profile on the Firefox Web Browser may be corrupt or may have malware sources.
Outdated Firefox- The outdated version of the Firefox app may cause this error.
The list of causes for which the XPCOM error occurs on Firefox is given in this section. How to Fix Mozilla Firefox Couldn’t Load XPCOM Error on Windows 10 The article addresses the error and the methods to resolve the XPCOM Firefox error are explained here. You may click on the OK button to close the error message, but you may not be able to use the Firefox app. The XPCOM is a cross-platform component model from the Mozilla Firefox, so the Cannot load XPCOM error disrupts the browsing. However, the Couldn’t load XPCOM error message pops up now and then. Mozilla Firefox is a trusted Web Browser and is compatible with most devices.