Do not regenerate meetings

By default, when a user accepts or tentatively accepts a meeting, Outlook creates a duplicate copy of the meeting with the new response status and a new entry ID. Outlook then deletes the old version of the meeting from the calendar. This setting allows you to roll back to the legacy behavior and prevent meeting regeneration.

Supported on: At least Windows 7
Registry HiveHKEY_CURRENT_USER
Registry Pathsoftware\policies\microsoft\office\16.0\outlook\options\calendar
Value Namedisablemeetingregeneration
Value TypeREG_DWORD
Enabled Value1
Disabled Value0

outlk16.admx

Administrative Templates (Computers)

Administrative Templates (Users)