Is OneDrive, Google Drive or iCloud Drive a backup?

Cloud services encourage the confusion. "Your files are safe in the cloud" is marketing that is true about exactly one failure and silent about the rest. It is worth being precise, because the precision is the whole of the advice.

Safety

Step by step

1. Name what sync guarantees.Sameness. Every signed-in device shows the same folder. Add a file on the laptop and it appears on the desktop. Change it, and the change appears. Delete it, and it disappears from all of them. The guarantee is that they match, not that anything is preserved.
2. Name what a backup guarantees.Preservation. A backup holds what the files looked like at a moment in the past, in a place the live machine has no authority over. Change or destroy the live copy and the backup still has what it had. That one-directional relationship is the entire definition.
3. List the five ways household data is actually lost.The drive dies. You delete or overwrite something by mistake. Ransomware encrypts everything the computer can write to. The house is burgled or burns. You lose access to the account. Sync covers exactly one of these — the dead drive — and it is the only one most people have planned for.
4. Test your own setup with one question.If I delete a folder right now and the machine syncs, is there a copy somewhere that nobody sitting at this computer can reach? If the answer is no, you have sync and no backup.
5. Add versioning, which is the cheap half-measure.Most sync services keep previous versions and a deleted-items area for a published period, typically about a month. That genuinely rescues an accidental overwrite noticed quickly. It does not rescue a loss noticed in a year, an account you cannot get into, or a bulk deletion you did not spot.
6. Add one copy that does not sync back.For most households that is an external drive holding a full copy, updated on a schedule and then unplugged and put somewhere else in the building. Unplugged is doing real work: a drive that is permanently connected is writable by ransomware and by a mistaken delete-all.
7. Keep the sync as well.None of this is an argument against cloud storage. Sync solves device loss completely, keeps your work available everywhere, and is the reason a stolen laptop is now an inconvenience. Two protections against two different failures.

Tips

• "Backup" on a sync service's marketing page usually means "we upload your folder". Read it as sync unless the service explicitly offers point-in-time restore of the whole account to a chosen date.
• A second computer signed into the same account is not a second copy. It is a second window onto the same copy.
• If you only do one thing from this page, copy your irreplaceable folders to a drive today and unplug it. Everything else is refinement.
• Shared folders owned by someone else are the weakest link in most households. If they remove the share or close the account, the files leave your machine too.

Common mistakes

• Counting devices as copies — Four devices showing a synced folder are four screens on one folder. A deletion reaches all four, usually in under a minute.
• Paying for more cloud storage and calling it a backup — The capacity changed; the relationship did not. A bigger mirror is still a mirror.
• Leaving the backup drive permanently plugged in — Anything with write access to your files — ransomware, a bad script, a mistaken select-all — has write access to that drive too.
• Assuming the deleted-items area is permanent — It is a grace period of a published length, and it expires quietly. It protects the mistake you notice this week, not the one you notice next year.

Questions people ask