Firefox コミュニティフォーラム

I was positively surprised recently when the new Firefox profile manager (about:profilemanager) was introduced. https://www.tech2geek.net/how-to-use-the-new-updated-profile-manager-in-firefox-2025/ is an article about that.

However, I thought it's just a new visual UI with an in-browser switcher for the existing profiles (that I already had setup). However, it does not appear so.

The differences I see:

1. 1. 1. old profile management

• was managed by `about:profiles` or when starting FIrefox with `-P`
• is saved in `~/firefox` and the `profiles.ini` clearly and quite obviously mentions them there, so it's easy to manage them.

I also found this old support article: https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

1. 1. 1. new profile management

• automatically asks on startup if more than one profile exists
• is managed by `about:profilemanager` or with the Firefox burger menu
• seems to be saved in `~/.mozilla/firefox/Profile Groups` (Linux path here) in some .sqlite files, and I do not quite understand the format. Not mentioned in `profiles.ini`.
• also, when you change something here (even like opening a profile?), you cannot open `about:profiles` anymore, because it says "Some Firefox process has made changes to your profile, […] you need to restart Firefox", only after a restart further changes would be possible, which I find quite confusing but it also indicates somehow the features belong together?

And this seems to be the new one: https://support.mozilla.org/en-US/kb/profile-management#w_whats-the-difference-between-profiles-and-multi-account-containers

1. 1. Questions

• What are the differences here (I may have missed)?
• How can the new profile feature save so few files? Is it technically called "profile groups"?
• And the most important: How can I migrate an old profile? (In order to use the new features and GUI etc. I quite like)

Crash submitted, ID = 320cc808-4505-4cba-6e0f-9f2c2955d007 Still happens in troubleshoot mode. Still happens with extensions disabled (Ublock origin, Proton Pass) Started happening since Dec. 5, 2025 System is current with all Debian?Ubuntu updates installed (daily refreshes) Linux Kernel 6.8 on Lenovo Yoga i7 (ca. 2022) with Intel i5 & Intel graphics

With Firefox 144, there is unasked for/unwanted AI introduced. How do I ensure that all AI is completely disabled in my browser? I found a link describing some settings, but want to confirm this will disable ALL AI in the browser. I don't want it, don't trust the privacy/security holes yet to be found and would prefer it was not included in Firefox to begin with. The list I've found is:

• user_pref("browser.ml.chat.enabled", false);
• user_pref("browser.ml.chat.menu", false);
• user_pref("browser.ml.chat.page", false);
• user_pref("browser.ml.chat.shortcuts", false);
• user_pref("browser.ml.chat.sidebar", false);
• user_pref("browser.ml.enable", false);
• user_pref("browser.ml.linkPreview.enabled", false);
• user_pref("browser.ml.linkPreview.optin", false);
• user_pref("browser.ml.modelHubRootUrl", "");

Will this do it? What about:

browser.ml.chat.nimbus

Do I need to clear that field to ensure I don't get some auto opt-in in the future as more and more of this "stuff" is put into the browser?

Why not leave Firefox as a security/privacy conscious browser and put out a separate AI browser (FirefoxML?) for those that are not as concerned. How does Mozilla ensure that no information is leaked through AI from sessions for professionals that must protect physician/patient, attorney/client information or other legally confidential information?

I have an Investors.com account and a feature they offer is a stock sector data table that shows recent performance and other information. When I try to open these tables they close immediately, but if I use my tablet with a different browser they will remain open. I believe this is a simple setting that I need to adjust, but I don't know enough to figure it out.