I've had 5 clients this week tell me that they cannot open the .pdf's I have created in Corel Draw. I have tried the Save As function, the Export Function, and the Publish to PDF function, and there doesn't seem to be a difference for the clients.
Other posts have suggested using a different program to open the files, but I have not control over what a client uses to open them.
I am running Corel Draw 2017 ver. 19.1.0.419, on Windows 10 Pro ver. 1709
That's strange, but maybe your clients tried to open the PDF using the e-mail client or browser and something is wrong. Also, sometimes Acrobat Reader display the PDF different than AdobeAcrobat (that's not relative to files made with CorelDRAW)
Have you tried using PDF/X-3 using compatibility with Acrobat 8.0?
No, but that's worth a shot