How to disable the Encrypt-Only feature in Outlook
Original KB number: 4493792
Summary
In Microsoft Outlook for Microsoft 365, when you enable Microsoft Purview Message Encryption, Encrypt-Only is added as a new ad-hoc template. Encrypt-Only enables message encryption without rights restrictions. This article describes how to disable the Encrypt-Only option in Outlook.
For more information about the feature, see Encrypt-Only option for emails.
More information
You can disable the Encrypt-Only option on the Encrypt list without also disabling Message Classification. To do this, apply the following registry key.
Warning
This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
In Registry Editor, locate and select the following registry subkey:
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\DRM
On the Edit menu, point to New, and then select DWORD (32-bit) Value.
Type DisableEO, and then press Enter.
In the Detail pane, right-click DisableEO, and then select Modify.
In the Value data box, type 1, and then select OK.
On the Edit menu, point to New, and then select String Value.
Type DefaultPermissionTemplateGuid, and then press Enter.
In the Detail pane, right-click DefaultPermissionTemplateGuid, and then select Modify.
In the Value data box, type irmdnf, and then select OK.
Exit Registry Editor.