This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Èròjà atẹ̀lélànà yii ni a ti fi pamọ́ fọ́jọ́ pípẹ́. Jọ̀wọ́ béèrè ìbéèrè titun bí o bá nílò ìrànwọ́.

After Updating and loading message windw apears "TypeError: Components.classes[cid] is undefined" why and what to do?

  • 2 àwọn èsì
  • 6 ní àwọn ìṣòro yìí
  • 1 view
  • Èsì tí ó kẹ́hìn lọ́wọ́ sergrop

more options

After upgrading to Firefox 6.0 after opening a small message window error opens with the message TypeError: Components.classes[cid] is undefined

After upgrading to Firefox 6.0 after opening a small message window error opens with the message TypeError: Components.classes[cid] is undefined

Ọ̀nà àbáyọ tí a yàn

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).

Ka ìdáhùn ni ìṣètò kíkà 👍 0

All Replies (2)

more options

Ọ̀nà àbáyọ Tí a Yàn

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).

more options

Thanks cor-el I solved the problem The offender was "OneClick YouTube Downloader 1.07" I removed it and FireFox works OK