Can I share a report I saved in one quicken data file to another quicken data file
A Quicken "saved report" does not contain the "report" itself: a saved report consists only of saved report "customizations". There is no way to copy saved report customizations from one Quicken file to another.
[You can "print" any Quicken report - saved, or not - to a PDF file; and that PDF file can be "shared" with any other computer.]I have no idea what the original poster means by saying, " ... the new data file is incomprehensible for creating similar reports".
I'm unaware of any new report customizations that could warrant that comment. In my experience, using the same report customizations in the newest Quicken edition/version/release will virtually always produce the same report those customizations produced in an earlier Quicken edition/version/release.
[A Quicken improvement I would support is the ability to display/print report customizations. I believe such an option would make it easier to find differences in reports created in the same, or different, Quicken files ... as well as to re-create reports from one file in a different file.]