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

just installed 4 and began getting this b/4 the home page opens:what happened:TypeError: Components.classes['@mozilla.org/extensions/manager;1'] is undefined

  • 1 reply
  • 8 have this problem
  • 6 views
  • Last reply by TonyE

more options

I just installed 4 and began getting this error message

TypeError: Components.classes['@mozilla.org/extensions/manager;1'] is undefined

I click ok and the home page opens, what is causing this to happen?

I just installed 4 and began getting this error message TypeError: Components.classes['@mozilla.org/extensions/manager;1'] is undefined I click ok and the home page opens, what is causing this to happen?

All Replies (1)

more options

That indicates that you are using an add-on that is not compatible with Firefox 4. For details of how to troubleshoot that see https://support.mozilla.com/kb/Troubleshooting+extensions+and+themes