Client-Side Limitation or Licensing Limitation?

Microsoft launched the new message recall feature for Exchange Online in October 2022 and shipped the code in early 2023. I duly wrote about the feature and noted the restriction for email protected by sensitivity labels. The EHLO blog describing message recall says:

Does recall work for encrypted email?

Message Recall within Classic Outlook is not available for messages encrypted with OME or using MIP labels. When attempting to recall these messages, the recall option will be greyed out in Classic Outlook and unavailable. This is a client-side limitation and is by design. To recall these messages, access your mailbox using OWA or the New Outlook for Windows, and recall your message from there.

Microsoft subsequently revamped the new message recall in August 2024. Nothing more was said about sensitivity labels. All we know is that a client-side limitation stops Outlook classic being able to recall protected messages while OWA and the new Outlook can both recall protected messages with ease (Figure 1).

Having the Right License is Always Important

Roll forward to message center notification MC882266 (last updated 23 October 2024, Microsoft 365 roadmap item 413431) where we discover that a component called Microsoft Purview Information Protection Advanced Message Encryption lies at the heart of the matter. According to the notification, user accounts must have a Microsoft 365 E5 or Office 365 E5 license to be able to recall encrypted email from their Sent Items folder. The same limitations that the mailbox must be in Exchange Online and that recall is only possible for messages sent to recipients within the same organization exist.

Notice that there’s no mention of client-side limitations. When such limitations are mentioned, it implies that some software problem exists within a client that prevents the client from being able to do something. Outlook classic is perfectly capable of working with sensitivity labels that encrypt messages.

In fact, Outlook classic is the most capable client in terms of working with encrypted messages because it can operate offline, including the ability to issue message recall requests for unprotected email by selecting a message and using the option in the File menu (Figure 2). The recall option isn’t available if the selected message has a sensitivity label with encryption.

Recall requests are kept in the Outbox folder until a network connection is available. Synchronization then occurs to send the recall request to Exchange Online for processing.

The ability of Outlook classic to work offline almost as well as when online is where the real issue might lie. OWA and the new Outlook are both designed to work online and that’s how they usually work. It’s therefore easy for the clients to check the licensing status of the signed in user, specifically to check that the account holds the Azure Information Protection Premium P2 service plan that’s included in the Microsoft 365 E5 and Office 365 E5 products. Outlook classic would need additional code to check user licensing when online so that it could work offline, much like the client stores rights management use licenses to allow it to work with protected messages when offline.

It can be argued that the limitation exists both in the client (can’t check a license unless Outlook classic is online) and licensing (can’t recall protected messages unless the right license is available), so the somewhat torturous text MC882266 is accurate without being clear.

Message Recall in Outlook Mobile

Meanwhile, message center notification MC1025213 (7 March 2025, Microsoft 365 roadmap item 471444) announces that Outlook for iOS and Android can recall messages. The option is available from the […] menu after selecting a message (Figure 3).  Outlook mobile clients cannot recall protected messages.

In Case of Protected Recall, Look for OWA

I’m not sure how many people will want to recall encrypted messages. If you find yourself in this situation, it’s easy to fire up OWA or the New Outlook and issue the recall request. Of course, the added time required to remember to use a different client and perform the message recall might mean that the recipient has read the text, but that’s a risk you must take.

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