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

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  • 7 have this problem
  • 3 views
  • Last reply by cor-el

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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?

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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)