Thanks for sharing the details!
Attaching a ZIP file as an OLE object in a Word document is not supported using OpenXML SDK alone. This is a platform limitation, not a coding issue.
This happens because OLE object embedding for files like .zip requires Microsoft Word Interop. OpenXML SDK cannot create OLE Package objects. Microsoft Word must be installed to embed ZIP files as OLE objects. Server environments usually do not support COM or Word Interop.
- Store the ZIP file on disk or server location.
- Insert the ZIP file as a clickable hyperlink in the Word document.