Empty attachment id if mail is digitally signed in Outlook desktop

[thowoi]

On Outlook desktop window.Office.context.mailbox.item.attachments returns an array of attachments with empty ids and zero size:

[
  {
    "attachmentType": "file",
    "contentType": "image/png",
    "id": "",
    "isInline": true,
    "name": "image001.png",
    "size": 0
  }
]

Note: Outlook Online works as expected with digitally signed mails.

Expected Behavior

Attachment id should be present in window.Office.context.mailbox.item.attachments array.

Current Behavior

Attachment id is an empty string ""

Steps to Reproduce, or Live Example

• Compose a new mail
• Add one or more attachments
• Digitally sign the message (How to add a digital signature)
• Send the message to yourself or some other recipent
• Enumerate the attachments with window.Office.context.mailbox.item.attachments and check the id values

Context

This blocks us from retrieving attachment contents via REST API/EWS API.

Your Environment

• Platform: PC desktop
• Host: Outlook
• Office version number: Microsoft 365 MSO (Version 2110 Build 16.0.14527.20234)
• Operating System: Windows 10 Enterprise (Version 20H2 Build 19042.1348)

[exextoc]

Thanks for reporting this issue. We are aware of this behavior, however, we don't have any timelines to share regarding it. Internal tracking id : Office 4714964.

[exextoc]

Would also like to add what is your scenario here? Are you trying to download the attachment contents? Or something else?

[thowoi]

Yes, it's for downloading the attachment contents. We are implementing a custom attachment encryption api.

[exextoc]

We've encountered difficulty in getting attachment ids from signed mails. We are exploring ways to enable this scenario (perhaps enable getAttachmentContentAsync) to work on these attachments, but we are still exploring this space and can't share when a solution would be implemented.

[ExternalMe]

We use this API to archive email attachments in our own cloud solution and make them accessible to our customers. Our customers trust that they can bring in any email and its attachments at any time. I am writing this comment in the hope to highlight the importance of a working interface and to encourage you, that this much needed feature will be implemented soon. It is incomprehensible to our customers that our solution does not work because Outlook offers a non-functioning interface.

I hope to hear from you guys soon.

[georgechr]

We also have this issue. It's annoying that Office JS is broken in this case

[egloff]

Same for us, hope this will be addressed soon...

[stephanmo]

We are facing the same problems. Please fix this @exextoc. MS promotes its new outlook where our old com-plugins do not work anymore and the new outlook addins are lacking such crucial functionality to read attachment contents

[Runja]

Are there any updates on this issue? Some of our customers are slowly switching to signed emails and suddenly we have to explain to them that our archiving/filing addin will no longer work properly. This is quite a hindrance for us.

[manuelsidler]

@exextoc any update on this issue?

[benjibauss]

Jup same here...any update?

[TimonGisler]

Is there any known way or workaround to access the attachments of digitally signed Outlook emails?

[stephanmo]

It has now been almost 3 years since this issue was reported, and there is still no information on whether and when this issue will be addressed. Could you please provide an update on the timeline regarding this matter? This issue is blocking a customer's go-live, as they will be switching to the new web-based Outlook add-in and will no longer be able to use our COM plugin (which can read encrypted attachments).

[b521f771d8991e6f1d8e65ae05a8d783]

We've encountered the same issue, Office.js is still faulty here.