The CPD file is actually a Microsoft Access database file using a custom file extension. If you open Microsoft Access, you should then be able to open the .CPD and examine all the tables and relationships inside.
I was hoping not to have to dive quite that deeply into it, especially since trying to make assumptions based on examining data structures without intimate knowledge of their use is never a wise idea
There is obviously (at least to me) much (perhaps most?) of the information contained in the .cpd data structure that is rebuilt from the rest of the project files - so I was hoping some experts could give me a short list of the kinds of things that would be stored in the .cpd that might be lost when the .cpd is automatically rebuilt. Then I could make a higher level decision of it those types of things matter to our use without having to get too far into the weeds...
Anyone else have any insights?
Given the fact that Adobe has added a feature that allows a CPD to be deleted before opening any project, I'm not sure anything is actually removed.
I thought Peter Grainge had documented some of these things over on his grainge.org web site, but I'm not finding what I thought he had. Maybe if you poke around on it you will have better results than I did.
The purpose of the CPD is to make RoboHelp work quicker. It can be deleted as when that is done, RoboHelp rebuilds it from many other files so it's not the CPD that is required.
Your method is creating an HHP file and you can use that to open it in RoboHelp. Have you tried that?
If you have and it did not work, then given that you have a method of creating a CHM, then see the page on my site about Reverse Engineering.
Also there is information in Opening Corrupt RoboHelp Projects that might help given the back door way you are working.
See www.grainge.org for RoboHelp and Authoring information