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

When I click on firefox to open in my Mac, an error shows up: plug-in object Type error: id is undefined. When I click on the OK button, firefox opens. This never happened in FF 3. What is this?

  • 3 replies
  • 6 have this problem
  • 1 view
  • Last reply by cor-el

more options

Also when I am in a site, such as an account, and click on a highlighted link, I get another error, {Javascript Application] can't create mcafee plug-in object: Type Error: components. classes [cid] is undefined. The only mcafee I had on my computer was the secure search and I uninstalled it, but I still get this message. When I click on the OK button with the error message, then the link opens up.

Also when I am in a site, such as an account, and click on a highlighted link, I get another error, {Javascript Application] can't create mcafee plug-in object: Type Error: components. classes [cid] is undefined. The only mcafee I had on my computer was the secure search and I uninstalled it, but I still get this message. When I click on the OK button with the error message, then the link opens up.

All Replies (3)

more options

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the add-ons is causing the problem (switch to the DEFAULT theme: Tools > Add-ons > Appearance/Themes).

  • Don't make any changes on the Safe mode start window.

See:

more options

Thanks that fixed it, it was mcafee site advisor and it corrected when I disabled it. Does this mean I can't ever use it with FF4?

more options

You're welcome.

You will have to wait for McAfee to release an update that fixes this issue. I've seen quite a few threads about this issue, so it happens more often.