With Cubase 15.0.20 i have found a bug.
When using Spectralayers (ARA) it saves the audio in SpectraLayers Edits on c:/ drive but not in the project folder.
Version 15.0.10 of Cubase works fine.
I have the same issue with 0.20.
Best
Magnus
In the SpectraLayers standalone, Check Preferences | System | External Edits Path
That just sets the location for the saving of edits. Before 0.20, a dialogue box used to open in Cubase asking to save - in my case - unmixed stems in the Cubase project folder, when dragging them from Spectralayers into the Cubase project in ARA mode.
This is no longer the case, which seems to be a bug to me.
Best,
Magnus