Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

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

every time I open firefox the following message appears: what happened:TypeError: Components.classes['@mozilla.org/extensions/manager;1'] is undefined" . After I press "OK" it continues, apparently normally.

  • 1 reply
  • 1 has this problem
  • 13 views
  • Last reply by Hasan

more options

Everytime I open Firefox the following message appears:


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

Everytime I open Firefox the following message appears: what happened:TypeError: Components.classes['@mozilla.org/extensions/manager;1'] is undefine

All Replies (1)

more options

Troubleshooting extensions and themes

Check and tell if its working.