I downloaded the software went through the set up process and now there is a grey screen with the Roon symbol. Its been that way for quite a while. I’m not sure if its importing or is just hung up. I am using a 2012 yosemite 10.10.3 mac mini. 8 gig of ram and a Western Digital External hard drive.
This sounds like a bug. The app is not intended to make you wait staring at a spinner while your music imports. @kevin will be in touch and can help you extract some logs for us to look at.