First, after further review, I believe this topic is meant for Windows, while my experience is with Adobe Acrobat Read DC under MacOS. This could be purely driver's fault under Windows (can't comment there).  Here is what I observe on MacOS: Every application that uses standard MacOS printing framework presents the user with the OS standard GUI, which includes duplex print option for the Brother printer I am using Reader offers printing features beyond what MacOS offers, so it is understandable that it uses its own dialog.  However, it could have passed the resulting output via the OS's printing framework.  Possibly it does not do that because it want to block the "Print to PDF" feature built into the OS. Reader's dialog is missing the duplex print option Chrome also uses its own print dialog on MacOS, but it does offer the duplex print option Since this works in Chrome and it does not in Reader, it points to an issue with Reader. ... View more

If what you said was correct, than the operating system would also not know about printer's duplex print capability. I think the fundamental issue is that Adobe fails to use the default print mechanism, or at least allow for print output to "Open in Preview", in which case duplex print would still be possible via the OS's capabilities. ... View more