We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

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.

Avatar for Username

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

This thread was archived. Please ask a new question if you need help.

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
  • 1 view
  • Last reply by cor-el

amrc
amrc
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)

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
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).