Hi, just checking is this set up properly : https://support.mozilla.org/en-US/kb/applications-panel-set-how-firefox-handles-files

This does not solve my problem. Please see the image capture.

Hi Wmbiird, the problem is that the server is sending a non-specific content type. Instead of specifying application/pdf it is sending application/octet-stream which is a generic content type that Firefox won't associate with a standard action, even if you tell it to do so.

(See attached screenshot.)

You might wonder why the site is using a non-specific content type when every webmaster knows how to identify a PDF, and the most likely explanation is that the site wants to force a download dialog, bypassing the behavior of showing a PDF in a tab.

Edit: There's a discussion of this content type here: https://developer.mozilla.org/docs/Web/HTTP/Basics_of_HTTP/MIME_types#Important_MIME_types_for_Web_developers

jscher2000:

Thanks for your reply. I read the link and the attachment and the explanation is above my pay grade. Why there is this difference is totally beyond me. As Firefox recognizes the file is a PDF, why should the response be different?

I initiated the download by clicking on a link.

If you're asking why Firefox doesn't just disregard the unhelpful content-type information and base its behavior on the file extension, I don't know the original reasoning, but it has always been that way. In another thread today, the server was sending a .png image file with the content type text/plain, so Firefox suggested opening it in Notepad. Webmasters are supposed to do things right.