Hey @Sari_Tanskala,
My apologies for the confusion eariler. @Geoff_Coupe is correct in that I shared the incorrect information around setting up sharing permissions.
As another test, could you temporarily set up your Mac as your Roon core, and see if you’re able to access the new folder/drive that way? You can do this by heading into your Roon Settings>General and disconnecting from your Nucleus. You can then select your Mac to be used as a temporary Core.
I’d make a backup as well if you haven’t scheduled one recently.
I’ll be on standby for your reply. 