I changed computers and upgraded to FileMaker 16 and am having this same issue. Anyone know what caused the change or how to reverse it?
In this case, its with PDFs. When landing on a layout with a PDF stored in a Container field (with container data stored externally), I'd like the user to see a thumbnail of the PDF, like before. But instead there is a popup window that says:
Do you want to open or save this file?
With the choices Open, Save and Cancel.
Also, whichever the user selects, there is no thumbnail.