Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

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

Every time I start up Firefox, I receive the following warning/message. Java Script Application. Type Error: Components.classes(cid) is undefined. How do I correct this?

  • 2 replies
  • 3 have this problem
  • 8 views
  • Last reply by T11646

more options

Question Every time I start up Firefox, I receive the following warning/message. Java Script Application. Type Error: Components.classes(cid) is undefined. How do I correct this?

Question Every time I start up Firefox, I receive the following warning/message. Java Script Application. Type Error: Components.classes(cid) is undefined. How do I correct this?

All Replies (2)

more options

Do you see a Last 7 days folder?

If not then older history has been deleted.
Firefox 5 doesn't use a time limit to store history like previous Firefox 3 versions did.

more options

Cor-el No 7-day history folder. I delete my history each time I quit Firefox. The problem still exists.