User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:15.0) Gecko/20100101 Firefox/15.0.1 Build ID: 20120905151427 Steps to reproduce: I set Firefox Preferences to: Privacy->+Clear history when Firefox closes->Settings->+Cookies Actual results: I closed Firefox but my cookies were not deleted. Expected results: The cookies should be deleted. Bug 443354 suggest that this behavior is caused by the setting: General->Show my windows and tabs from last time This setting does not only restore the URLs but the complete sessions even if in conflict with the privacy settings. Since privacy should have higher (if not highest) priority, only the URLs should be restored while the cookies should be deleted in this case.
This is only a duplicate of bug 401187 if bug 401187 is not about rewording but resolving the problem of FF not deleting cookies. Until this has been confirmed it is not a duplicate.
http://zpao.com/posts/restore-previous-session/ Set both settings to 2; It works for me.