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

Error at start-up: JAVA Script what happened:TypeError: Components.classes['@mozilla.org/extensions/manager;1'] is undefined

  • 8 replies
  • 1462 have this problem
  • 543 views
  • Last reply by pimpdaddy

more options

his message is displayed on Firefox start-up:

Box title is "JAVA Script Application"

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

All Replies (8)

more options

That is an indication that you have an incompatible add-on. Follow the procedure in the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article to identify the culprit.

more options

Foxit Toolbar is a likely suspect if you started receiving this message recently. The error stopped happening for me the instant I disabled this add-on.

Modified by fizzbowen

more options

@ghosking

Your above posted system details show outdated plugin(s) with known security and stability risks.

  1. Shockwave Flash 10.0 r42
  2. Next Generation Java Plug-in 1.6.0_18 for Mozilla browsers

Update the Java plugin to the latest version.

Update the Flash plugin to the latest version.

more options

This could also be caused by the Ask Toolbar. Can you disable that and try again?

more options

If you have the Ask Toolbar installed under Firefox 4.0b1+ it will give this error. The toolbar lies in its install manifest to say it is compatible with up to Firefox 5.* (you heard me) thus you'll need to disable or uninstall it. A blocklist request is pending...

more options

It happens to me when I installed a new release of skype (5.5). Yust disable the plugin and the problem will fixed.

Modified by Zaphod56

more options

I concur that the problem is an add-on that is incompatible with FF5. Disable it and reboot. Problem solved.

more options

Thank u very much for your post, cuz u were right on the money! After chasing the problem for hours last nite, installing, uninstalling etc.; I stumbled across your post here thankfully. Thank u once again!