The registry key HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity is a critical component of Microsoft Office's . It stores settings, cached data, and configuration parameters related to the user's signed-in identity used across Office applications (Outlook, Word, Excel, PowerPoint, etc.).
Administrators can control identity behavior via for Office. Relevant policies:
Inside ...\Common\Identity , you may find the following subkeys and values (names vary by Office version and update channel).