If you're looking for my old blog posts, they can be found at http://old.abettergeek.com/.
Boy howdy, this one is annoying.
Windows 10 has a built-in PDF printer. That's pretty awesome…except the print driver is really basic. It's so basic, it doesn't allow you to add custom paper sizes. I'm working on a print project that uses junior/half sheets, which are 5.5×8.5“. I needed to create a PDF from multiple copies of a range of pages in an InDesign project, and since there's apparently no way to do this with InDesign's built-in PDF export tool, I needed to do this as a print job, instead.
It turns out there is a way to add paper sizes - it's just not obvious at all…and it requires local admin rights. If you can get that far, here's what to do.