Newest Outlook version doesn't open pdf in Acrobat

FOUND A SOLUTION THAT WORKS FOR ME: MOZILLA FIREFOX.

I have encountered the problem of opening a pdf attachment from an Outlook incoming email.  Read through all the threads and found no solutions.

Then, being as I would rather use Firefox, instead of Edge (or whatever it is called these days), I clicked on the "Tools" button in the toolbar, scrolled down to "Settings" at the bottom, then in the General default section on the left, I scrolled down to "Applications" and typed pdf in the search box.  Being as I already had Adobe Acrobat installed, I selected "Use Adobe Acrobat" as the Action for "Portable Document Format."

It's been working for me ever since.

BTW, today, I just switched from our old server/workstation hardware to a new server/workstation environment, and that is when I encountered the same problem many have complained about --- Outlook opening a pdf in a distinct tab.

I rarely use Edge anyway.  Also, I'm using an older 64 bit version of Adobe Acrobat, version 2025.001.20474, that allows me to keep the "File, Edit, View, HIstory, Bookmarks, Tools, Help" toolbars at the top.

Good luck guys and gals.

McGillicuddy