Good morning from Italy, 6.20am. In recent days I read about Renoise here on the forum, it is a daw that I did not know, in Italy it is not very widespread it seems. I am a very curious person, so I decided to install the demo and try it, maybe buy it in the future. I’m starting to understand the basics of software using the built-in sounds and have enjoyed using Renoise as a sequencer for the Rack, using MIDI Clock and opening the software separately. At this point I was intending to experiment with Rack VST in Renoise as well, but Renoise can’t find it. The VST folder is already present in the settings, but it does not appear to me among the instruments to load. Do I have to buy Renoise, or should the VST also work in the demo and I need to check some settings better?
what OS are you using?
Win10
you should download the lasted version of the VCV Rack pro for windows, and make sure have the vst checkbox mark for install
if renoise do not find the rack, go to preferences >> plug/misc and check for rescan previously failed plugins , then pres re-scan
if you have installed the vcv rack vst in other location , add this location in the vst 2 area (in the preferences windows too) pressing the browse button.
go to your plugin tab and press the button “no plugin loaded”
the vcv rack should be listed in the vst area
I m not sure if there are a limitation in the demo version, I think not , but take a look in the renoise page
Solved, it was my stupid mistake. The VST folder was present in the settings, but disabled 
a click was enough.
Thanks!