How to get ContentBytes for a .msg attachment in an email message

Question

Hi, we have an application that downloads email attachments using the contentBytes tag returned by https://graph.microsoft.com/v1.0/me/messages/A{{messageId}}/attachments/{{attachmentId}}

This works fine for all attachment types including .eml attachments in Outlook for Mac, apart from .msg attachments in Outlook for Windows where no contentBytes tag is returned.

Is there a way to get contentBytes for .msg attachments?

Thanks

Answer 1

Hello Andrew Earl,

Greetings from Microsoft Support!

It sounds like you’re encountering an issue with .msg attachments in Outlook for Windows using Graph API. The contentBytes property is not directly available for .msg attachments because they are treated as itemAttachment rather than fileAttachment.

To retrieve the content of a .msg attachment, you can use the $value segment in your request URL. Here’s how you can do it:

1. Get the attachment details:

GET https://graph.microsoft.com/v1.0/me/messages/{messageId}/attachments/{attachmentId}

1. Retrieve the raw content:

GET https://graph.microsoft.com/v1.0/me/messages/{messageId}/attachments/{attachmentId}/$value

This will return the raw contents of the .msg file. Please check documentation.

Hope this helps.

If the answer is helpful, please click Accept Answer and kindly upvote it. If you have any further questions about this answer, please click Comment.