Could you make sure your Firefox is not set to Automatic private browsing mode? On the Options page, switch to the Privacy & Security panel and scroll down to the History section. Do you have either of these: * Firefox will: Never remember history * Firefox will: Use custom settings for history + [x] Always use private browsing mode Those are incompatible with keeping session history. ''If you are not using automatic private browsing:'' Could you check whether there is a policy set that might affect startup. To see that, type or paste '''about:policies''' in the address bar and press Enter to load that internal page. Are there any active policies?