Check the destination path
Confirm that the destination application uses the folder where you placed the save. A correct file in the wrong location is effectively invisible.
Check the filename and extension
Make sure the filename and extension were not changed accidentally during copying.
Check the version
If the save worked on the old installation but not the new one, compare the software versions before attempting more invasive changes.
Restore the backup
If an experiment made things worse, return to the untouched backup rather than repeatedly editing the same file.
Test one change at a time
Change one variable, test the result, and record what happened. This prevents a troubleshooting session from becoming impossible to retrace.