There was thread some time ago called "Allow ability to send secure emails without requiring a file attachment.". The thread was closed citing that this feature was added into V2.4. How does one find or enable this feature?
On the Compose Message page, you need to click on the "Private Message" checkbox, then the message can be sent without attachments.
That option is not available on my Compose Message screen... any other ideas? It is visible on the Help screenshot so I know where it should be but it's not an option on my screen!
When you don't see the Private Message checkbox then this feature needs to be enabled for your Group in the Admin interface: In "Admin > Groups > edit > Message Settings > Private Message" enable checkboxes: "Enable Private Message as default" and "Users in this group can change the Private Message option"