Could you double-check that you are not starting up in automatic private browsing? With that setting, all windows are in a private browsing session, but Firefox runs in a "stealth" mode where there is no visible indication that the windows are private windows. Here's how to check that on the Options page: "3-bar" menu button (or Tools menu) > Options In the left column, click Privacy. On the right side, check for either of these: * "Firefox will: Never remember history" * "Firefox will: Use custom settings for history" ''and'' the checkbox for "Always use private browsing mode" is selected Both of those indicate automatic private browsing. ---- If you are not using automatic private browsing, then it sounds as though either Firefox is broken or one of your add-ons may be blocking private browsing. Could you test in Firefox's Safe Mode? In Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem. ''If Firefox is not running:'' Hold down the Shift key when starting Firefox. ''If Firefox is running:'' You can restart Firefox in Safe Mode using either: * "3-bar" menu button > "?" button > Restart with Add-ons Disabled * Help menu > Restart with Add-ons Disabled and OK the restart. ''Both scenarios:'' A small dialog should appear. Click "Start in Safe Mode" (''not'' Refresh). Any difference?