Hey Mark,
Right now we don’t support a configurable location for your Roon database on Windows, so it’s always going to be on your C:\ drive.
We strongly recommend running your Roon database on an SSD, so you’d need to replace the existing C:\ drive here – this will give you a serious performance boost, not just for Roon but for your Windows PC in general.
There are lots of tutorials out there about moving to a new Windows system drive (like this one), but I’ve moved this thread over to the Software section of Community, in case you have any questions. Let us know!