We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

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.

Avatar for Username

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

XULRunner error popup; firefox auto-install

  • 1 cavab
  • 0 have this problem
  • Last reply by cor-el

John Lilley
John Lilley
more options

I've been having this annoying popup about XULRunner encountering an error. From what I've read, XULRunner is a legacy integration with Firefox. Sure enough, I see Mozilla Firefox installed. But un-installing it doesn't help. Soon, it is re-installed, and the error comes back. I have a feeling that some application is using XULRunner and Firefox as a component, but I don't know what it could be. Is there any way to find out, and stop that application from installing Firefox and XULRunner? Or at least getting its problem fixed?

I've been having this annoying popup about XULRunner encountering an error. From what I've read, XULRunner is a legacy integration with Firefox. Sure enough, I see Mozilla Firefox installed. But un-installing it doesn't help. Soon, it is re-installed, and the error comes back. I have a feeling that some application is using XULRunner and Firefox as a component, but I don't know what it could be. Is there any way to find out, and stop that application from installing Firefox and XULRunner? Or at least getting its problem fixed?

All Replies (1)

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
more options

An error message like XPCOM missing or about platform version or entry points not found can happen because of a failed Firefox update that left you with a mixture of old and updated files in the Firefox installation folder. This can happen in case security software was keeping a handle of some of the files in the Firefox program folder preventing Firefox from replacing all the files.

You need to reinstall Firefox and possibly remove the Firefox program folder to ensure that all files are replaced. You may have to disable security software temporarily in case the problem persists.

Reinstall Firefox:

Helpful?

Sual ver

You must log in to your account to reply to posts. Please start a new question, if you do not have an account yet.