Using classic Outlook for Windows in business environments
Thanks, adding the registry key HKCU\SOFTWARE\Microsoft\Office\15.0\Common\Identity\EnableADAL as you described solved the problem for me. Outlook 2013 running in Win 10 Pro now auto logs on to Microsoft Exchange without repeatedly asking for a password. Don't know why Microsoft didn't notify Outlook 2013 users of this in advance or automatically make the registry fix via an automated software update.