Yes, because you're on a Mac. XPS was invented by Microsoft and the main tools for dealing with it are included with Windows. Nothing to do with Acrobat, though it can convert them using Microsoft's tools.
So my Mac Acrobat won't open .xps files?
I wouldn't expect it to.
OK. Her is the real scoop on XPS files and Acrobat.
Under Windows, Acrobat can open and convert an XPS file to PDF (assuming of course, you direct the Acrobat open dialog to open *.* files). The XPS is not displayed by Acrobat; the result of the conversion is. You can then choose to save the resultant PDF file to the file system.
Contrary to the assertion above, the conversion of XPS to PDF in Acrobat is done via Adobe's own code. No “Microsoft tools” are used in the conversion at all!
Under MacOS, Acrobat simply doesn't support opening and conversion of XPS to PDF. Why? Simple. Despite Microsoft's best efforts to make XPS a “PDF killer,” XPS never did become popular. Too little, too late. It remains today primarily as an under-the-covers spooling format for Windows and not a very good one at that. As such, given how few XPS files you might find on Windows systems, they are as rare of hen's teeth on MacOS systems. In fact, this is the first time I have seen someone even ask about this for MacOS.
If you are really hot to open XPS files under MacOS, you can find some third party applications on the MacOS application store that can do this chore.
Thank you. I hadn't even heard of an xps until this job so I will just deal with the workaround.
Thanks for the correction. I didn't realise Adobe had ever gone into reading XPS.