Apps · App updates after a move
What happens if a moved app is damaged by a failed update?
Short answer: For self-updating apps, Storage Studio keeps a safety copy on your fast drive. If an update damages the moved app, it restores it from that copy and notifies you.
For apps that update themselves in place — the kind most likely to be damaged — Storage Studio keeps a safety copy of the app on your fast drive when it moves it. If it later finds the moved app damaged, typically by a failed self-update, it restores the app from that copy and tells you: "… was restored … The app is working again."
The safety copy lives on the external drive, so it doesn't use space on your Mac.