Leo, I've found this Select text from PDF preview - #6 by abr and disabled "Adobe PDF for Vista" and "Microsoft PDF" to get a fall back to Adobe Acrobat Reader DC (which is now my default when I double click the PDF file), but finally Opera doesn't preview and shows the error text as I posted above.
Spent now 3 hours of Sunday afternoon for this - instead of doing the PDF renaming work. My wife won't be happy 