External drives · Space on the drive
What happens when my fast drive runs out of space?
Short answer: Moves that won't fit don't start, and one that runs out of room part-way stops without deleting anything. Free space on the drive, move items back, or upgrade with Transfer Drive.
Moves that don't fit don't happen. Storage Studio checks for room before moving, and tells you "There isn't enough room on your fast drive" rather than starting something it can't finish. If a drive fills up part-way through, the move stops, nothing is deleted, and your originals stay where they were.
To make room, move items you no longer need on the drive back to your Mac, clear out your own files stored elsewhere on the drive, or upgrade to a bigger drive with Transfer Drive.