Forum Discussion
Drag-drop *.msg into document library: cannot open attachments. Nor copy e-mail from OWA to library.
The SPO preview of an email shows the presence of attachments but they cannot be opened without downloading the email and then using the local email client (e.g. Outlook) to open the attachment.
If you want to open the attachments in the email preview (in the browser) you will need to use 3rd party tools. These tools offer other benefits like extracting email metadata such as subject, from, .. into SharePoint columns during uploading and allow for directly attaching SharePoint documents to emails. There are several companies active in this space. See e.g. https://directory.collab365.community/office365-sharepoint/sharepoint-email-management-software/
Note: I am affiliated with one of the vendors listed
Paul | SLIM Applications
Email attachments need a location to be processed. And then, attachments should be presented via a link. Without a processing location/Document Library in SharePoint, natively email attachments can not be displayed.
I don't think that Microsoft will introduce a solution soon enough to fix this issue.
There are third-party add-ins that does the job. All of them, use a temporary location (Document Library) in SharePoint to display the attachments. However, following add-in has more benefits than just previewing the emails with attachments.
https://fleximal.com.au/products-services/sharepoint-online-search/
It even recursively go inside the email attachment. For example, if there is an email attached inside an email, it will render the second email as well.