Prevent users from adding new content to existing PST files
Supported on: At least Windows Server 2008 R2 or Windows 7
Registry
HKCU
software\policies\microsoft\office\16.0\outlook\pst Value name: pstdisablegrow
Enabled: pstdisablegrow = 1
Disabled: pstdisablegrow = 0
Description
This setting prevents users from adding any new content to PST files linked to their profiles.