Missing pieces in Stud.io – Digital LEGO: Tools, Techniques, and …

Since a few Stud.io versions on my Mac I have to hit the ‘Hide unavailable parts in the selected color’ filter a few times until it really becomes active because on opening Stud.io I have the parts list behavior you describe. Looks like I had that option selected. I turned it off and those pieces were showing again!

 https://www.eurobricks.com/forum/forums/topic/193992-missing-pieces-in-studio/