Duplicate files · Removing and restoring duplicates
What happens if my files changed since the last duplicate scan?
Short answer: Storage Studio re-checks the copy you're keeping right before removing anything. If it has moved or can't be read, nothing is removed and you're asked to scan again, so an out-of-date result can never cost you the last copy.
Storage Studio re-checks at the moment of removal, so an out-of-date result can't cost you the last copy. On your Mac, the copy you're keeping must still be present and readable; if it isn't, nothing is removed and you'll see "The copy you're keeping couldn't be verified, so nothing was removed."
In a cloud account, the kept copy is checked in the account itself just before anything is removed; if it has gone, you'll see that nothing was removed and you should scan again.
If you've reorganised a lot since the scan, click Scan now for a fresh list before cleaning.