Just recently got my 6P and have been loving it. I own a Nexus 7 Tablet and have no problem opening PDFs on it. However I cannot open any of (these same pdfs) on the 6P.
1. Yes they pdfs are not corrupted. They open fine on both my desktop (Adobe Reader) and on the Nexus 7 (Adobe App).
2. I have the Adobe App on the 6P doesn't work. Using the Google PDF reader (packaged with Marshmallow) doesn't work. Kindle App opens the pdf but takes forever to render each page.
3. The files were moved from desktop to the device's internal storage. I am using File Manager to view these files because the download app doesn't work either.
Bonus points: for anyone that can clearly tell me how to get it to forget the "Always Open" with this app on this OS. It is not in settings and there seems to be no other place to get it to "forget" a selection. I actually had to delete adobe in order to get it to forget the choice.