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Now I am getting this error message when I open Firefox "what happened:TypeError: Components.classes['@mozilla.org/extensions/manager;1'] is undefined" Then when I click on okay Firefox opens. How do I get rid of that error message?

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  • Last reply by cor-el

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I try to open Firefox and I get this error message "what happened:TypeError: Components.classes['@mozilla.org/extensions/manager;1'] is undefined" then when I click on ok the browser opens. I have tried reinstalling Firefox but that does not take care of the problem. What can I do? What is wrong?

I try to open Firefox and I get this error message "what happened:TypeError: Components.classes['@mozilla.org/extensions/manager;1'] is undefined" then when I click on ok the browser opens. I have tried reinstalling Firefox but that does not take care of the problem. What can I do? What is wrong?

All Replies (5)

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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).

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Thank you so much. Following your advice found out it was an add-on from a new program I had installed. I disabled the add-on and now it works fine. Really appreciate your answer and Firefox, my favorite when it comes to the internet.

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You're welcome

Can you tell us which Add-on caused the problem?

It helps others with the same or a similar problem who read this thread.

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It was from this site: http://www.tracker-software.com/ A tracker add-on comes down with their PDF viewer. I don't even know what it does. I disabled it then I removed it. Now Firefox works fine.