Hi Esteban, I think that should only appear after an update. If it appears at every startup, possibly it has been added as a second "home page" or is a pinned tab.

On the Preferences page, Home panel, when Custom URLs is selected, there is a field listing home page(s). It can store multiple URLs separated by vertical bar ("|") characters. So that's the first thing to check. See: How to set the home page.

Pinned tabs have only the site icon, not the title, so that's easy to rule out. More info: Pinned Tabs - keep favorite websites open and just a click away.

Another possible explanation might be something in a user.js file. Firefox will read that optional file at startup, if it exists, and use its contents to override your regular settings. This article describes how to check for that file: How to fix preferences that won't save.

Any progress so far?

You can possibly try Firefox from the official Mozilla server if you currently use a version from the repositories of your Linux distribution to see if it behaves differently.

• https://www.mozilla.org/en-US/firefox/all/#product-desktop-release

I'm very sorry, it was my mistake. I run Firefox from RAM and then save my profile to disk, but the script I use wasn't working because it found a lock file left in the profile's temporary folder. Thank you very much for trying to help, and apologies again.

Thank you for reporting back. It's always good to understand the situation.

Is there any way to permanently disable this message? Firefox updates often and it's already a hassle to restart it after every update. The message is 100% useless and serves only the amusement of the Firefox developers and graphic artists. As a user, it is nothing but spam. How can I disable this message?

You can try to set this pref to false on the about:config page.

• browser.aboutwelcome.enabled = false