Since the update to version 38, just installed, restart previous session is no longer working automatically on startup. It merely opens up the default browser page in a single tab. The button to Restart previous session works when pressed but this used to occur automatically. Nothing has been changed, only the update from 37 to 38. PS. Note to Mozilla support site owners: On the support forum, might it be a good idea to put a "start new topic" button somewhere? It took me ages to find a method of opening a new question and I only found it by a chance. It really is not obvious when starting from the top https://support.mozilla.org as to how to open a new topic.