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When I start Firefox, Iget the following message "TypeError: Components.classes[cid] is undefined"

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  • Last reply by cor-el

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TypeError: Components.classes[cid] is undefined. This is the message thast pops up every time I start Firefox.

Chosen solution

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).

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Chosen Solution

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).