Arunkumar Ravindran

Currently, in the Dynamics 365 timeline, attachment preview functionality depends on the MIME type of the file. For example, if a PDF file is attached to an email, but its MIME type is incorrectly set as application/octet-stream (which sometimes happens when emails are sent from external systems), the attachment cannot be previewed, although it can be downloaded and opened correctly.

We expect the system to identify the file type based on the file extension or content when the MIME type is incorrect or generic. This will help avoid manual intervention to correct the MIME type (application/pdf, for example) using platform-level API calls or customization.

Expected improvement:

• Allow the attachment preview to function based on the actual file type, even if the MIME type is not explicitly correct.
• Improve user experience by eliminating the need for manual MIME type corrections.

Scenario tested:

1. Uploaded the same attachment in a draft email → Preview works as expected.
2. Received the same attachment from an external sender → Preview does not work because the MIME type was application/octet-stream.

Impact:

This enhancement will improve usability for customer service agents and other users working with external emails containing supported attachment types (e.g., PDF, images).