How Folio keeps your archive safe
Analysis never changes anything
Scanning, identification, duplicate analysis and previews are read-only. They do not modify your files and do not create files inside your sources.
Removal is recoverable
Cleanup you approve moves copies to the Windows Recycle Bin, where you can put them back. Folio counts a copy as removed only when Windows confirms it is in the Recycle Bin. Where Windows cannot guarantee a copy can be restored, Folio refuses and says why: on USB flash drives and SD cards, on exFAT drives, when the Recycle Bin is off or too full, and for a file larger than the Recycle Bin.
Folio will not propose removing every copy of a photograph. At least one always remains. There is no permanent delete in Folio: emptying the Recycle Bin is your decision, made in Windows.
Evidence, not guesses
Two files are called duplicates only when they are byte-for-byte identical. A shared filename or matching size is a hint, never proof. A group of duplicates appears only once its copies are verified identical. Photographs that merely look alike are not detected.
Backups stay backups
A copy on a different physical drive may be a deliberate backup. Folio notes which copies share a drive, and a copy you mark Keep as backup is never offered for removal, including when you let Folio choose. Without that mark, Let Folio choose keeps exactly one copy of each photograph.
Marking a copy to keep records your intention. It is not evidence that a backup exists or has been checked, and Folio will not claim otherwise.