Upgraded from Music Maker 16 to Music Maker 23 Premium. I am attempting to load a project (MMM) fie created on version 16. Errors out, I am unable to load file
You need to remember that MM 16 is a 32-bit program, MM 2023 is exclusively 64-bit. I suspect that may be the reason your earlier project will not open in the latest version.
The advice which @SP. has given you may be the only method by which your old project can be resurrected.
The title of your post says "UNABLE TO LOAD MMM FILE" -- is this the actual error message, or is it something different?
As others have commented, the actual MM program went from 32-bit to 64-bit, and it may be that the structure of the project files also changed. But I couldn't find any reference in the current (MM2023) Help docs. You might want to contact Support directly, to verify whether there are compatibility issues.