Freeing up space · What's Using Space (Storage Inspector)
Why is the Move back button missing or greyed out on a relocated folder?
Short answer: The folder can't be moved back cleanly right now. Hover the disabled button for the reason; the row's orange or red warning line also shows whether moving back is still possible.
Because the folder can't be moved back cleanly right now, and Storage Studio would rather tell you than try. The button is replaced by a disabled lookalike — hover it and a tooltip explains why.
The row's warning line gives a hint too: it's tinted orange or red depending on whether moving back is still possible. Common causes are the fast drive not being connected, or something about the original location having changed. Fix the cause and the button returns. If the row is actually broken, a red Delete chip appears instead — see broken rows.