Hello, my name is***** to Justanswer! Give me just a few minutes to look up some specifics, I'm working on this now.
Sometimes RAM is the only issue with an Avid product. Give me the full details of your computer, and your interface that you are using.
I see the problem. Sibelius 8 only works with 10.9 or 10.10. The rest of your computer is compatible. You're seeing bugs that weren't built for your OS version.
Avid does not have qualification to write their programs for 10.12 yet. Your best bet is to revert back to the earlier versions in the meantime.
Yes, the 64 bit versions.
64-bit Windows 7 (SP1 or later), Windows 8.1 (not Windows RT) or Windows 10
Click here for all of the compatible versions.
Please don't forget to rate 3-5 stars for my knowledge and service to you.
I sent you right to the Avid site. http://avid.force.com/pkb/articles/en_US/Compatibility/en418691
You said you had Sibelius 8. You will need to downgrade your OS, or upgrade Sibelius to 8.4.2.
That's not Sibelius 8 when we're talking about software... I'll opt out, good luck.