I see forms of this being addressed in other posts but not one that has been answered as far as I can see.
I use Acrobat Pro DC to compile a series of screenshots into PDF format. I then try and fail to open the file in Acrobat Pro DC...I get the error message "Adobe Acrobat could not open...because it is either not a supported file type or because etc"...
But the file opens fine in Mac Preview!
I did notice that in the process of creating the pdf, there's a progress bar at the bottom that never goes past "checking security" or something like that...but then the file's created.