Yea, this isn't going to work. I don't know about earlier OS but Finale 2011 and earlier will not install correctly in Yosemite or later. I suspect this is also true of 2012 but I cannot confirm this. In addition, there are many performance issues in Yosemite and later that were not resolved till 2014.5.

For testing, I tried installing 2011 on a Yosemite test drive a few days ago — the license manager will not present the serial# to the server (this will be the drive i test OS 10.13 when it's released). I was going to contact support on this when I remembered, "Oh yea, this doesn't work."

Registered users have an upgrade path to Finale 25. You can log into your MM user account and do it online or go through your favorite reseller. Do not use the Chrome browser to upgrade — Safari and Firefox work fine.