User Configuration > Administrative Templates > Microsoft PowerPoint 2016 > Disable Items in User Interface > Predefined
User
HKCU\software\policies\microsoft\office\16.0\screenrecorder
This policy setting allows you to control the initial audio recording setting for a screen recording in PowerPoint. By default, audio is recorded during a screen recording. If you enable this policy setting, audio isn’t recorded during a screen recording. But, the user can choose to turn on audio recording manually in the UI. If you disable or don’t configure this policy setting, audio is recorded during a screen recording. The user can choose to turn off audio recording manually in the UI.