User Agent: Mozilla/5.0 (Windows NT 5.1; rv:29.0) Gecko/20100101 Firefox/29.0 (Beta/Release) Build ID: 20131222030204 Steps to reproduce: 1. Browse some sites 2. Set browser.privatebrowsing.autostart to true 3. Restart Firefox Actual results: The old history is still there but can't be cleared because "Clear recent history" is disabled. Expected results: "Clear recent history" should still be enabled.

This is by design. What you see there is the history from the other (non-private) session and not the private one. "Clear recent history" is disabled because there isn't any 'recent private history' to clear. Anyway, you can still get rid of that either by clearing it from the non-private session or from Tools/Options/Privacy/Clear all current history.