Adobe Acrobat Reader could not open 'XXX name of file' because it is either not a supported file type or because the file has been damaged (for example, it was sent as an email attachment and wasn't correctly decoded).
MacAir - MacOS 10.13.6
I have uninstalled every version of Adobe, reinstalled Reader to version 2019.021.20061.
Some PDFs open, some don't.
I scanned documents thru an HP Envy 4500. I do that almost literally daily. No problem till now so I'm really not feeling that it's the scanner.