Cloud sync keeps selected files aligned across devices. A backup preserves a recoverable copy from an earlier time or separate location. A sync service may offer version history or a recycle bin, but that feature has its own limits and retention period. Sync alone should not be treated as a complete backup strategy.
A useful example
You accidentally overwrite a document on your laptop. Sync sends the new version to your other devices. If you have usable version history, you may recover the earlier document; if the retention window expired, the synced copies may all contain the mistake. A separate backup with tested restore gives another path.
A five-minute test
Choose a harmless file, check whether an older version can be previewed and restore it to a different location. Confirm it opens without overwriting the current file. CISA's
ransomware guidance recommends maintaining copies and testing recovery. The practical question is not "Is it in the cloud?" but "Can I recover the version I need after a mistake or attack?"
Practical distinction
Check both the version-history retention and a separate restore path. A file appearing on two devices is two synced views, not necessarily two independent recoverable copies.
