Downloaded .MSG messages (with attachments) open in New Outlook but do not display the attachments. Attachements only appear when opened in Classic Outlook.

Question

We are experiencing an issue when reviewing documents, whereby the .msg files containing attachments, do not show the attachments in New Outlook. This leads us to mistakenly think they have not been attached. However when we open these same .MSG files in Classic Outlook the attachments are displayed.

Answer 1

Duplicate of
https://learn.microsoft.com/en-us/answers/questions/5886665/downloaded-msg-messages-(with-attachments)-open-in

Answer 2

Dear @saimicro poster,

Good day, and I appreciate the clear explanation of your concern. From my understanding, downloaded .MSG messages can be opened in the new Outlook, but the attachments are not displayed, which may make it appear as though they were not included. I attempted to reproduce this in my test environment and was able to view attachments correctly in both the new Outlook and classic Outlook. That said, I have also come across recent reports from other users experiencing similar behavior, which may suggest a broader issue affecting the new Outlook.

For problems of this nature, I recommend that the Global Admin in your organization create a service request with Microsoft Support. A technical support engineer can perform a remote session to investigate the situation, verify the backend configurations, and run any necessary synchronization tools to resolve the problem. If the issue requires further attention, they can escalate it to a specialized team for deeper analysis. For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin. If you don't know who your IT administrator is, please refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support 

In the meantime, as a workaround, you may consider using classic Outlook to open .MSG files with attachments:

• Right-click any .msg file > Open with > Choose Outlook (classic).
• Or set Classic Outlook as the default app for .msg files:
• Right-click a .msg file > Open with > Choose another app > Select Outlook(classic) > Check "Always".

I know this isn't the answer you were hoping for, and it's disappointing when the solutions aren't straightforward. Please know that as a forum moderator, directing you to the correct, specialized support is the most effective help I can provide in this situation. Should you have any further questions or need additional assistance, please don’t hesitate to reach out. I am always happy to help. Wishing you all the best, and have a wonderful day!

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Answer 3

New Outlook does not fully support working with saved .MSG files in the same way as Classic Outlook. Classic Outlook is the MAPI-compliant client and is the version designed to correctly interpret and display all elements of .MSG files, including embedded attachments.

Because of this limitation, .MSG files that contain attachments may open in New Outlook without showing those attachments, even though they are present and visible when the same file is opened in Classic Outlook. This is a client capability gap rather than a problem with the .MSG file itself.

For reliable review of downloaded .MSG messages and their attachments:

1. Open .MSG files in Classic Outlook instead of New Outlook when verifying attachments.
2. If double-clicking a .MSG file opens New Outlook, adjust the default file association so that .MSG files open with Classic Outlook, or start Classic Outlook first and then open the .MSG file from within it.
3. When working with attachments generally, use Classic Outlook if complete attachment handling is required, as New Outlook has known limitations around some attachment and integration scenarios.

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References:

• Open, save, and edit attachments received in Outlook
• Troubleshoot attachment problems in Outlook for Windows
• Double-clicking a .msg file opens an unexpected version Outlook
• Office 365 apps insist on using Outlook Classic to share documents to email - Microsoft Q&A