This error usually occurs when an email message contains a significant number of MIME (Multipurpose Internet Mail Extensions) bodies, which can overload the email server or cause performance issues. To overcome this problem, please follow the steps outlined below:

  1. Split the Email into Multiple Parts: If the problematic email contains large attachments or embedded images, try splitting the email into smaller parts. You can divide the attachments into separate emails or compress them into a compressed file (e.g., ZIP) and send them as a single attachment.

  2. Reduce the Number of Recipients: If the email has a large number of recipients, consider reducing the number of recipients or sending the email to smaller groups of recipients. This helps alleviate the load on the email server.

  3. Use File Sharing Services: Instead of attaching large files directly to the email, you can utilize file sharing services such as Dropbox, Google Drive, or OneDrive. Upload the files to the respective service and share the download link with the recipients in the email.

By following these steps, you should be able to overcome the "This message was not processed because it contains a large number of MIME bodies" error in Outlook. If you continue to experience difficulties or have any further questions, please let me know, and I'll be glad to assist you.

Thank you for your understanding and cooperation.