Graph Api Download Email Attachment C# Updated May 2026

Typically a GraphServiceClient initialized with ClientSecretCredential . 1. Identify the Message and Attachment IDs

var attachment = await graphClient.Me.Messages["{message-id}"] .Attachments["{attachment-id}"] .GetAsync(); if (attachment is FileAttachment fileAttachment) { byte[] contentBytes = fileAttachment.ContentBytes; await File.WriteAllBytesAsync(fileAttachment.Name, contentBytes); } Use code with caution. Method B: Downloading the Raw Content Stream microsoft graph api - How to retrieve ItemAttachment bytes graph api download email attachment c#

An application registered in Azure Portal with the Mail.Read permission. Method B: Downloading the Raw Content Stream microsoft

There are two primary ways to retrieve the file content depending on the SDK version and your specific needs: Prerequisites Before you begin, ensure you have: For

Method A: Using FileAttachment and ContentBytes (Recommended for Small Files)

Downloading email attachments using the Microsoft Graph API and C# is a common task for automating document processing and data integration. Whether you are using the Microsoft Graph SDK or making raw HTTP requests, the process involves authenticating, retrieving the message's attachment metadata, and then accessing the actual file content. Prerequisites Before you begin, ensure you have:

For files under 3 MB, the content is often returned as a base64-encoded string in the ContentBytes property. You must cast the generic Attachment object to a FileAttachment to access this property.