Sync Is Not Backup — and the Difference Costs People Their Files

What sync actually does

Sync keeps two locations identical. That is its purpose and it does it well: edit a file on your laptop and the change appears in the cloud within seconds.

The problem is the word identical. Delete a file and it is deleted in both. Encrypt a folder with ransomware and the encrypted version is propagated. Overwrite a document with an empty one and the empty one wins. Sync has no opinion about whether a change was intended — it simply makes both sides match.

Most people discover this the way you would expect: by noticing that something is missing everywhere at once.

What a backup does differently

A backup only ever adds. New files are copied across. Changed files are copied alongside the previous version rather than on top of it. Files removed at the source stay in the backup.

Nothing in your backup is ever overwritten or deleted. A file that changes at the source is copied alongside the old one as "photo (backup 2026-08-25).jpg", so the previous version is still there. Deleting a file from the source does not delete it from the backup.

That single property — append-only — is what makes a backup survive the thing you actually need protection from, which is not usually hardware failure. It is a mistake, a bad sync, or software behaving badly.

Why provider trash is not the answer either

Every major provider keeps deleted files for a window: Google Drive and Dropbox for 30 days, OneDrive for 30 to 93 depending on the account. That is genuinely useful and it is not a backup.

It expires, usually before anyone notices an old file is gone. It lives inside the same account, so losing access to the account loses the trash with it. And it protects against deletion, not against a file being quietly replaced with a worse version months ago.

What a second cloud gets you

Backing one cloud up to a different provider gives you something the first cloud cannot: independence. A suspended Google account, a billing failure, an accidental mass delete, a shared folder someone else cleared out — none of it reaches a copy sitting in pCloud or Dropbox under a separate login.

Cloud Combo copies between providers on a schedule, server-side. Nothing downloads to your machine, so a 500 GB Drive can be backed up from a laptop that is closed five minutes later.

Every file is checked on arrival against the destination provider’s own hash — Dropbox returns a content_hash, OneDrive and pCloud return a hash we compare — so a copy that did not land intact is sent again rather than counted.