I am running Musicator 4 very successfully on Windows 10 32-bit.
It will not run on 64-bit.
I am a music teacher with thousands of files and Musicator is simply the best notation program that used to be available. I have tried MuseScore, Finale and Sibelius 7 and all of those are far too complicated and do not give me the flexibility that Musicator does. My old Musicator 4 is intuitive and I use it every day.
I use a Roland UM-One MIDI interface to connect my PC to my Yamaha Clavinova CVP-105 and I can access hidden MIDI codes so that I can use the complete range of voices available on the Clavinova by having created my own custom *.mod text file which Mus4 uses. Owing to the way that Microsoft have set up Windows, the MIDI cable must be unplugged, then plugged in again before MIDI is available. I am using a dual-boot PC with a 1GB SSD on which I have both 32-bit and 64-bit Windows 10 running. I've had Mus4 running on various OS for about 20 years and it's simply the best that's available.
If someone brought out an updated version of Musicator I would be the first to buy it but in 2021 there's nothing which compares favourably with it.