I had the same problem the first try. I trashed my current (2018 MegaPack) installation, and it installed fine. Of course, if you're not wanting to do a full clean install (downloading all the real-tracks again...) this isn't a solution.

I'm upgrading from 2018MegaPack to 2019 Ultra - so I have lots of RealTracks to download anyway.

I also put in a message to support, so we'll see what they say.