This can be caused by a problem with using "Restore Previous Session" as the startup setting, so if you restore the session automatically on the next start then try to disable this feature.

• Options/Preferences -> General -> Startup

Once the Bookmarks Toolbar is visible then you can restore the startup setting and check if the Bookmarks Toolbar stays visible on next starts.

Cor-el... This seems to have worked. But I have to add that I am back to version 63.03 now. Just going back a version did NOT do the trick last night. Your suggestion at first did not because strangely after unchecking the restore last session it rechecked on its own. I opened another profile once (no extensions/addons) and closed it with the same box unchecked. I opened my desired profile and unchecked again, closed it, then opened and the Bookmarks Toolbar is back. Then MySessions 2.9.8 got me back where I wanted. Alas... Now I am afraid to upgrade to version 64 ;(

Might I suggest backing up ~/.mozilla/firefox/{hash}.default/{profiles.ini,prefs.json,bookmarkbackups} prior even if that is temporarily in ~/Documents or your OS equal. then re-import prior to restarting a session on the upgraded version. (this is general upgrade advise not just to your question)

Sounds good thanks

Hi lepiane, the vanishing Bookmarks Toolbar is not a new issue in Firefox 64. It was first reported by a handful of users in Firefox 61 and its cause(s) remain unknown.

jscher2000 said

Hi lepiane, the vanishing Bookmarks Toolbar is not a new issue in Firefox 64. It was first reported by a handful of users in Firefox 61 and its cause(s) remain unknown.

Thanks. I noticed in some replies several months ago but I wasn't a fan of the solutions. So far I'm OK again doing the above.