Policy
Permanently remove all deleted content from PST and OST files
By default, a small percentage of deleted data is not overwritten in Outlook PST and OST files. By enabling this setting, all deleted data in PST and OST files is overwritten when users exit Outlook.
PackMicrosoft Office
CategoryMicrosoft Outlook 2016 / Miscellaneous / PST Settings
Policy ID
9da4c130b9a9Internal name
L_PermanentlyremovealldeleteditemsRegistry
Copy registry mappings
HKCU\software\policies\microsoft\office\16.0\outlook\pst\pstnullfreeonclose (enabled) = 1
HKCU\software\policies\microsoft\office\16.0\outlook\pst\pstnullfreeonclose (disabled) = 0Policy notes
By default, a small percentage of deleted data is not overwritten in Outlook PST and OST files. By enabling this setting, all deleted data in PST and OST files is overwritten when users exit Outlook.
Related policies
Default location for OST filesDefault location for PST filesDo not send meeting forward notificationsLarge PST: Absolute maximum sizeLarge PST: Size to disable adding new contentLegacy PST: Absolute maximum sizeLegacy PST: Size to disable adding new contentPreferred PST Mode (Unicode/ANSI)Prevent users from adding new content to existing PST filesPrevent users from adding PSTs to Outlook profiles and/or prevent using Sharing-Exclusive PSTsPST Null Data on DeleteUpgrade only the default store