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!

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.

what happened:.... this is the popup message TypeError: Components.classes['@mozilla.org/extensions/manager;1'] is undefined

  • 1 reply
  • 84 have this problem
  • 1 view
  • Last reply by cor-el

collinge
collinge
more options

Just upgraded to Version 5 - same problem.


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


This is the popup message I get when starting up Firefox. When I ok or kill the popup Firefox seems to work. This problem started when I upgraded the Windows 7 and install the latest Firefox (version 4 I think) about two months ago. Occurs on both the desktop and laptop. Any suggestions? Thanks

Just upgraded to Version 5 - same problem. " TypeError: Components.classes['@mozilla.org/extensions/manager;1'] is undefined" This is the popup message I get when starting up Firefox. When I ok or kill the popup Firefox seems to work. This problem started when I upgraded the Windows 7 and install the latest Firefox (version 4 I think) about two months ago. Occurs on both the desktop and laptop. Any suggestions? Thanks

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).