When you installed, was it with Admin privileges? Did you run the second installer for Aria/Garritan? Is this a fresh install or an upgrade from a previous version?

Sorry not sure what you mean "Admin Privileges".  I'm the only person who uses this program on one computer.  This is an upgrade from 2014.  It worked fine from the time I installed it (when it first came out - I always upgrade immediately) until a few weeks ago.  Then I began to have issues with crashes.  Would appreciate any help.  Thanks!

When it asks for a password to update software etc., you type in an Admin(istrator) password. You have privileges. Often, shared computers and networks are set up so you can't do this. 

I recently dealt with a problem cause by the 25 installer not doing it right, no matter how many times I ran it. 

Here's an easy way to test: Open a browser window, copy and paste in the following and hit Enter or Return:

file:///Library/Application Support/MakeMusic/Finale/Plug-ins

This should show a screen with your plugins folders—if so, it probably isn't an installer problem.

If it gives a File not found error, I have something you can try to force the installer to behave.

I would reset the Finale preferences. See here for info:

https://makemusic.zendesk.com/hc/en-us/articles/115002541107-Resetting-Finale-s-preferences-using-a-tool-crashes-Finale-etc-