$ ls /mnt/backup-1
ls: cannot access '/mnt/backup-1': Input/output error
$ ls /mnt/backup-2
ls: encrypted by ransomware (.locked)
$ folder3 restore --latest
Verifying snapshot 2026-08-05T03:00Z … checksum OK
✓ 1,284,772 files restored. Zero data loss.
$ exhale
Why a third copy
The first two copies share your fate.
Your local backup and your NAS live in the same building, on the same network, behind the same login. Whatever gets your data — ransomware, fire, theft, a fat-fingered delete that syncs everywhere — usually gets them too.
Folder3 lives somewhere else entirely: offsite, encrypted and versioned, in Folder3 account storage outside your building. When copies one and two go down together, the third one is the reason it's an incident report, not a resignation letter.