Two of my 3 gmail accounts work fine on my Win10 PC (OS installed yesterday without my specific consent - 'over' Win 8.1). My 'third' gmail account WILL NOT OPEN (not synced - whatever that is). (On my other [Win 7] PC, this same gmail account works fine; while a different gmail account is the one that won't open). Have tried all 'settings' options that were mentioned online, etc (everything seemed to be set up "OK" when I checked). This problem had been noted/ reported online as a problem circa July 2015. My Win 10 is up to date.