A similar question was asked 4 years ago, when Firefox 13 introduced lazy loading: How do I make Firefox 13 Load All My Tabs on Startup or when Resuming Reload

Firefox 13 (Released June 5, 2012) has introduced a new default setting to Load Tabs on Demand. This causes the browser to only restore the currently selected tab when resuming a session on startup, after a crash, or on a requested reload. I really don't like how I now have to click each tab and select restore. How can I turn this off?

My problem is, the solution found there (going to options => "General", or later "Tabs", and then unchecking "Don’t load tabs until selected") doesn't work anymore: since the new version 47, that option seems to have been removed.

Is there a new way to force Firefox to load all tabs when resuming a session?

3 Answers 3


I wanted the same and I found the answer here >> https://support.mozilla.org/en-US/kb/allow-firefox-load-multiple-tabs-background:

This applies to versions 47 and up.

When you restart Firefox and restore your previous session, Firefox will wait until you select a tab before loading it. This keeps Firefox running quickly and smoothly.

If you've allowed an earlier version of Firefox to simultaneously load multiple tabs in the background (offered as the "Don’t load tabs until selected" check box in the Preferences menu), when you upgrade to version 47 and up, your setting will reset to allow only one tab at a time.

You can change it back through your about:config preferences (advanced users only):

  1. In the address bar, type about:config and press Enter.

    The about:config "This might void your warranty!" warning page may appear. Click I'll be careful, I promise! to continue to the about:config page.

  2. Search for browser.sessionstore.restore_on_demand.
  3. Change the value to false.
  4. Close the about:config tab to save your changes.

Allowing Firefox to load tabs simultaneously can slow down its startup.

  • 4
    Half of the settings and add-ons I have installed in Firefox are to fix features they intentionally "broke" in subsequent releases. After several decades as a loyal user, I have finally switched to Vivaldi because I wouldn't put up with it any more. I still have Firefox installed for the very rare page that Vivaldi doesn't handle correctly. Usually, it works better than Firefox on rendering pages.
    – Joe
    Jun 14, 2016 at 17:28
  • Ditto, although Vivaldi went the same path for tabs lazy loading: at first it wasn't available, now it's enforced :(
    – user14764
    Jun 15, 2016 at 8:48
  • It is not a clear solution. After enabling it, FF didn't asked to restore and the second window (from restoring manually) didn't load in background all the tabs. Jan 6, 2017 at 7:33
  • Thank you! When I have to restart FF I'd like all my open tags (only 3-4) to load up.
    – Bulrush
    Sep 30, 2017 at 11:10
  • still working for firefox 60.2
    – Jovasa
    Jun 8, 2018 at 17:23

For those who don't want to load all the tabs on startup, my solution was to pin the few tabs that I want always available and keep the rest lazy-loaded by default.

  • 1
    I think this is a good solution, but pinned tabs by default are tiny. I had to enlarge them with userChrome.css and then set toolkit.legacyUserProfileCustomizations.stylesheets=true in about:config to make FF use userChrome.css!
    – EM0
    Jul 10, 2023 at 8:00

As of Firefox 68, browser.sessionstore.restore_on_demand no longer works. The workaround I found is using an extension that will reload all tabs when clicked, which also loads in any unloaded tabs. This s the one I used: https://addons.mozilla.org/en-US/firefox/addon/reload-all-tabs-in-window/

  • Have you tried browser.sessionstore.restore_tabs_lazily, which I found mentioned there notepad.patheticcockroach.com/1368/…? I guess at some point they just renamed the setting without migrating the previous one... they like to make us miserable :/
    – user14764
    Nov 24, 2022 at 15:08

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