Allow Firefox to load multiple tabs in the background

Revision Information
  • Revision id: 145312
  • Created:
  • Creator: Joni
  • Comment: updated for < 48
  • Reviewed: Yes
  • Reviewed:
  • Reviewed by: heyjoni
  • Is approved? Yes
  • Is current revision? No
  • Ready for localization: Yes
  • Readied for localization:
  • Readied for localization by: heyjoni
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Revision Content
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. This is Firefox's multiprocess feature.

Is the multiprocess feature turned on?

Your version of Firefox may be using the multiprocess feature already. Follow these instructions to make sure:

  1. Type about:support in your address bar.
  2. In Multiprocess Windows, if the number is higher than zero (0), you already have the multiprocess feature activated.

If the number is zero (0), follow these instructions to turn it on:

  1. Type about:config into your address bar.
  2. Look for browser.tabs.remote.autostart and set it to true.
  3. Restart Firefox to enable multiprocess.

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 PreferencesOptions 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. Type about:config in the address bar and press EnterReturn.
    A warning page may appear. Click Accept the Risk and Continue to go 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.