I am currently the only user in my office that has upgraded to 2019. Because other users sometimes need access for revisions, I always backsave to 2017. They are still not able to open these files, and neither can I, when testing opening with 2017 on my machine. Note that I can still open all files through version 2019 on my machine."Error Reading *File Path Name*.cdr file."
Oh that can't be good. : /
If accessing via network, try doing this locally on your machine?