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.

Rohkem teavet

When I open Firefox it gives this error, ReferenceError: mtRpt is not defined, and then open normally. How do I fix it?

  • 1 vastus
  • 7 on selline probleem
  • 3 views
  • Viimati vastas cor-el

more options

When I open Firefox it gives this error, ReferenceError: mtRpt is not defined, and then open normally. How do I fix it?

When I open Firefox it gives this error, ReferenceError: mtRpt is not defined, and then open normally. How do I fix it?

All Replies (1)

more options

This issue can be caused by an extension that isn't working properly.

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).


In Firefox 4 you can use one of these to start in Safe mode:

  • Help > Restart with Add-ons Disabled
  • Hold down the Shift key while double clicking the Firefox desktop shortcut (Windows)