Finale 26. Catalina is not going to run anything that isn't 64-bit, and you might as well get the current version as try to find Finale 25.

I have the same problem.

I have a school computer and had to upgrade to Catalina. Now my FINALE 2014.5 does not work.

This is what my computer tells me when I try to open my FINALE 2014.5:
"The developer of this app needs to update it to work with this version of macOS. Contact the developer for more information."

So is the only answer FINALE can give us is to buy the newest version?

This isn't really an issue on Windows, so the fault lies with Apple, not MakeMusic. If you want to run Finale on computers that must have the latest Mac OS, upgrade to Finale 26.

Fault? A curious choice of words. Let's look at the history... Apple announced that 64 bit only was coming 10 or 13 years ago depending on what press releases you believe. Many companies had released 64 bit versions of their apps and plugins by OS 10.8.

Finale 2012 was announced as being 64 bit to coincide with Apple's initial announcement that Yosemite would discontinue 32 bit support. There are what? a few hundred furious rants (a few thousand?) about this on the old forum—that was 9 years ago.

As it turns out, Apple kicked the can 8 years down the road. Finale 2012 and 2014 were released 32 bit only. Finale 25 was released 64 bit a couple years before Catalina finally did what was promised in Yosemite. 

Since some companies in business still haven't released 64 bit versions of their apps, I applaud MM for making it happen earlier than required. Unfortunately, this means that a nearly 7 year old version of Finale (2014.5 was a free update to 2014 released in 2013) no longer runs on the Mac beginning with Mojave (except for a few users and I don't understand how) and won't run at all in Catalina.

And for the record, 25 requires that Windows be in 64 bit mode. Those incapable of this or unwilling to change from 32 bit cannot run 25 or 26. 

Thanks for the history, Mike H.! I can still use 2014.5 and previous versions on the latest Windows, though. Not being able to use new software on old hardware should be expected.

Should be expected? Really? That’s funny. I’ll have to remember that when I try to install 26 on my Windows XP machine. Oh wait...

Hey, Mike H., I think you misread my comment....there's a *NOT* at the beginning of the last sentence.

In any case, it is a Mac OS issue isn't it? From what I understand, though Finale 25 is 64-bit, it is not compatible on Catalina. Finale 26 is required. Meanwhile on Windows 10, I can run 26, 25, 2014.5, 2008, and other older notation software.

Question, so if I get a new Mac running Catalina and the latest version of Finale, will I be able to open my old Finale 2012 files?

Yes, but they will open in F26. You may have to reset the “Open With...” if you try to open them with a double-click, but opening from within Finale should be fine.

And if you have articulations (accents, staccato, etc.) above chords, you may not want to apply the new Finale 26 "stacked articulations" update when you open the old file, since this can add multiple accents, staccatos, etc. above chords entered in older versions of the program.