Outlook password prompt with Office365

Office 2013 — Office 365 Modern Authentication

By default, Office 2013 will attempt to use Basic Authentication first, which will require users to re-authenticate every time Outlook is opened. To avoid authentication prompts, the following registry entries will need to be added.

 

Enable modern authentication for Office 2013

 REGISTRY KEY  TYPE VALUE
HKCU\SOFTWARE\Microsoft\Office\15.0\Common\Identity\EnableADAL  REG_DWORD 1
HKCU\SOFTWARE\Microsoft\Office\15.0\Common\Identity\Version REG_DWORD 1

 

Force modern authentication

 REGISTRY KEY  TYPE  VALUE
 HKCU\SOFTWARE\Microsoft\Exchange\AlwaysUseMSOAuthForAutoDiscover  REG_DWORD 1

 

NOTES:

Office 2016 defaults to use modern authentication, so no additional changes are required.

Office 2010 is not capable of using modern authentication.