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Error opening FF 8 "TypeError: Components.classes[cid] is unidefined"

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  • Last reply by petero

petero
petero
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I've just upgraded from FF 3.6 to FF 8. Every time I open FF 8, I get this error dialog box:

[JavaScript Application]

TypeError: Components.classes[cid] is unidefined

I just performed the upgrade, so haven't used FF 8 enough yet to know if the error causes any problems.

Thanks for your assistance.

I've just upgraded from FF 3.6 to FF 8. Every time I open FF 8, I get this error dialog box: [JavaScript Application] TypeError: Components.classes[cid] is unidefined I just performed the upgrade, so haven't used FF 8 enough yet to know if the error causes any problems. Thanks for your assistance.

Chosen solution

That 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 or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

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cor-el
cor-el
  • Top 25 Contributor
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Chosen Solution

That 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 or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

petero
petero Question owner
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Thanks, cor-el! FF started without the error in Safe Mode, so I disabled all the add-ons that had compatibility warnings, then enabled them one by one. It was AVG Safe Search that was causing the error.