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!

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

This thread was archived. Please ask a new question if you need help.

An error message says an illegal version of Firefox tried to install.

  • 1 reply
  • 1 has this problem
  • 2 views
  • Last reply by cor-el

Yuridad
Yuridad
more options

An error message says an illegal version of Firefox update tried to install and I should contact my administrator.

An error message says an illegal version of Firefox update tried to install and I should contact my administrator.

All Replies (1)

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

This issue can be caused by the presence of leftover files in the Firefox program folder (defaults\pref) like a file firefox.js that overrides the update URL with a wrong link.

Do a clean reinstall and be sure to remove the Firefox program folder to remove the file(s) that cause the problem.

See: