Delta Drive, Delta Trust & My Drive · Using Delta Drive
What happens if a Delta Drive file changed somewhere else while I was editing it?
Short answer: Nothing is overwritten. If the file changed elsewhere while you had it open, your version is saved beside it under a name saying where it came from, and the app tells you. Both copies stay in your drive.
Your edit is never allowed to overwrite a newer copy. If the file changed somewhere else while you had it open — on another Mac, in a browser, or by somebody you shared it with — your version is saved beside it under a name that says where it came from.
The window tells you this happened and waits for you to acknowledge it. Both copies are in your drive, so nothing is lost; compare them and keep what you need.