This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

message appears at startup and apps- how to rid this? what happened:TypeError: Components.classes[‘@mozilla.org/extensions/manager,1’] is undefined

  • 1 reply
  • 1 has this problem
  • 5 views
  • Last reply by cor-el

more options

what happened:TypeError: Components.classes[‘@mozilla.org/extensions/manager,1’] is undefined

message appears - want to rid

what happened:TypeError: Components.classes[‘@mozilla.org/extensions/manager,1’] is undefined message appears - want to rid

All Replies (1)

more options

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).