Policy
Disallow On Slow Connections Only Download Headers
This policy setting allows you to turn off the "On Slow Connections Download Only Headers" option. If you enable this policy setting, you will turn off the "On Slow Connections Download Only Headers" option in the Download Preferences menu in the Send/Receive tab. If you disable or do not configure this policy setting, you will allow the "On Slow Connections Download Only Headers" option in the Download Preferences menu in the Send/Receive tab.
386605829d0b L_DisallowOnSlowConnectionsOnlyDownloadHeadersFileCachedExchan Registry
Copy registry mappings
HKCU\software\policies\microsoft\office\16.0\outlook\cached mode\noslowheaders (enabled) = 1
HKCU\software\policies\microsoft\office\16.0\outlook\cached mode\noslowheaders (disabled) = 0 Policy notes
This policy setting allows you to turn off the "On Slow Connections Download Only Headers" option. If you enable this policy setting, you will turn off the "On Slow Connections Download Only Headers" option in the Download Preferences menu in the Send/Receive tab. If you disable or do not configure this policy setting, you will allow the "On Slow Connections Download Only Headers" option in the Download Preferences menu in the Send/Receive tab.