Allow Active X One Off Forms
Supported on: At least Windows Server 2008 R2 or Windows 7
Registry
HKCU
software\policies\microsoft\office\16.0\outlook\security Options
allowactivexoneoffforms enum - Load only Outlook Controls
->
0 - Allows only Safe Controls
->
1 - Allows all ActiveX Controls
->
2
Description
By default, third-party ActiveX controls are not allowed to run in one-off forms in Outlook. You can change this behavior so that Safe Controls (Microsoft Forms 2.0 controls and the Outlook Recipient and Body controls) are allowed in one-off forms, or so that all ActiveX controls are allowed to run.