Disallow Convert Document (Excel, PowerPoint, Word)

Supported on: At least Windows Server 2008 R2 or Windows 7

Registry

HKCU software\policies\microsoft\office\16.0\common\general

Value name: convertdocument

Enabled: convertdocument = BlockConvert

Disabled: convertdocument = AllowConvert

Disallow users to convert files that are in compatibility mode via the "Convert" command for Excel, PowerPoint, and Word.