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when I open Firefox, I get following message, "Java Script Application Type Error: Components. classes (cid) is undefined. What's wrong?

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  • Last reply by cor-el

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After a system restore and downloading of Firefox, every time I open Firefox, I get error message; Java Script Application Type Error: Components.classes (cid) is undefined. I am able to get rid of error message by clicking on close.

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This issue can be caused by an AVG extension.

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).