Finale 2012, 25 - Mac OSX 10.11.6
You have to enter the pickup in the score - in a part won't work. Once you do that, the first full measure will be measure #1, as you want.
Click the "Submit a request" button to communicate with Make Music directly. I doubt most anyone here understands your question.
What is in the dmg file? If it is the Finale 2014 installer and you have moved to the latest version then I would say yes, trash it.
Quit Finale and restart. If that doesn't work, shut down the computer and restart. Does that work?
This is a known problem, referred to as the "Virtual Stuck Key Syndrome" by members of the old Make Music forum. As you've found, quitting and restarting Finale sometimes works, but occasionally sh...
Use a "hard space" - on Macintosh, "option/space".
You can make a Staff Style for this. Under "Define Staff Style", click "New" and check the Transposition Box. Set the transposition to be the same as your Horn stave and additionally check "Set to ...
I would Retranscribe the notation (MIDI Menu). Be aware, though, that doing so will strip out any expressions, slurs, articulations, etc. that appear in the file. If there aren't any of these, Retr...
Use Part Voicing - see here: https://usermanuals.finalemusic.com/Finale2014Mac/Content/Finale/Part_voicing.htm
The music font is set to Helvetica, which of course is not a music font at all. Open the file, and under the Document Menu > Set Default Music Font choose Maestro. That will fix things.