Hello AVSLloyd.
We apologize for the inconvenience caused, as per the description above, you are not able to open a PDF file using Acrobat Pro DC on your Mac machine, Is that correct?
Please check for any pending updates of Acrobat from help>check for updates, reboot the machine after installing the updates and try opening any PDF file.
You can also refer and try the suggestions from the following Adobe article Can't open PDF
Try opening few files with Acrobat by going to Window>Cascade>Tile and see if that brings up the PDFs.
If you still experience any issue, please share the following information so that we can assist you in a better manner:
Let us know how it goes and share your findings.
Regards,
Anand Sri.