Fix Outlook for Mac Sending Emails Without Attachments
Question details
Users experience emails sent via Outlook for Mac being delivered without their attached files (such as Word, PDF, images, or PowerPoint) despite the email appearing to send successfully.
- Product
- Microsoft Outlook for Mac
- Device & OS
- Mac
- Scenario
- Sending emails containing document or image attachments using the Outlook for Mac desktop client.
- Observed behavior
- Messages are sent successfully, but attachments are stripped out and are missing from both the recipient's inbox and the sender's Sent Items folder.
Ensure your Outlook for Mac client is updated to the latest version and verify your internet connection before attempting to resend any missing files.
Verify and Resend the Missing Attachment
Use this manual workaround to confirm if an attachment was stripped during sending and securely resend the files to your recipient.
This specific issue has been identified as Microsoft 365 incident EX637339. It affects a small percentage of outgoing messages because of a service conflict in how attachment IDs are detected prior to sending.
Immediately after sending an email with attachments, navigate to the 'Sent Items' folder in your Outlook for Mac client.
Open the sent email. If the Word, PDF, or PowerPoint file is missing from the sent copy, the recipient did not receive it.
To maintain the email thread, click 'Reply' or 'Reply All' on the affected message within your Sent Items folder.
Click the paperclip icon to reattach your necessary files, verify they appear in the draft, and click 'Send' again.
Create Flawless Attachments with WPS Office
While resolving Outlook's sending glitches, ensure the documents you attach are perfectly formatted and fully compatible. WPS Office is a lightweight, completely free Office alternative for Mac that lets you create stunning Word, Excel, and PowerPoint files ready for email sharing.
- 1. Download WPS Office: Get the free WPS Office suite for Mac from the official website and install it.
- 2. Create Your Document: Open WPS Writer, Presentation, or Spreadsheet to create and format the files you need to share.
- 3. Save and Attach: Save your document in a highly compatible format like .docx or .pdf, and attach it to your Outlook email.
Frequently Asked Questions
Why did my Outlook email send without the attachment?
This is currently a known Microsoft 365 service issue (Incident EX637339) where the system conflicts with attachment IDs, causing Outlook for Mac to deliver certain emails without their attached files.
How can I tell if my recipient received the attached files?
Go to your 'Sent Items' folder in Outlook for Mac. If the attachment is not visible in your sent copy of the email, it was stripped during the sending process and the recipient did not receive it.
When will this Outlook for Mac attachment bug be permanently fixed?
Microsoft is actively monitoring and deploying fixes for Incident EX637339. You can check the Microsoft 365 Service Health dashboard (portal.office.com/servicestatus) to track the resolution progress.
Can file size cause attachments to disappear in Outlook for Mac?
While this specific issue is caused by a service bug, attachments can also fail if they exceed the size limits imposed by your email provider (typically 20MB to 33MB). Ensure your files are within the allowed size limit.
