Hi

That depends on how you are installing Windows 10 and Music Maker 2015 (MMM) as follows:

1. Windows 10 already installed on computer or is a fresh install followed by MMM - there should be no problems.
    
2. Windows 10 upgrade from Windows 8.1, 8  or 7 - you may have one of two problems :
    

           MMM loses its activation and requires reactivating.- however reactivation
           succeeds.
 

           MMM loses it activation and will not reactivate, you may also find other
           programs eg Microsoft Outlook cannot send emails or other applications,
           eg Firefox, cannot connect to the Internet or some websites  - see
           below for fix.

There is a known problem with upgrading from a previous version of Windows which can be fixed - see Most helpful reply here - note you may have to repeat this procedure at least twice and preferably 3 times - be aware this will take several hours !

HTH

John EB