Change the Maximum Number of Restorable Tabs in Firefox

The Session Store feature of the Mozilla Firefox web browser can restore all the previously open tabs and windows when your Firefox browser restarts in case of a crash. The Session Store has a setting of how many tabs it can restore in such a situation. The default value is 10 tabs but you can modify it to increase or decrease the maximum number of restorable tabs. Here is how :

  1. Start Mozilla Firefox.
  2. Type about:config in the location bar and press Enter.

    Open Configuration Editor in Firefox

  3. Firefox will show a warning. Click on the button labeled I’ll be careful I promise. to proceed.
  4. In the Filter field type session. You would see a preference named browser.sessionstore.max_tabs_undo as shown,

    Change Max Undo Tabs in Firefox

  5. Double click on browser.sessionstore.max_tabs_undo to change its value. You can enter any postive integer you want. The default value is 10. If you enter a very small number then only that many tabs would be restored upon a crash. If you enter a large number, then it might make Firefox sluggish.
  6. After changing the value, restart the browser for the changes to take effect.

For more information, you can consult the Mozilla knowledgebase article here : http://kb.mozillazine.org/Browser.sessionstore.max_tabs_undo.