Sync is not a backup. Here’s the difference.

Two jobs that look similar

Sync keeps a working collection of files consistent across locations. Backup gives you a recovery copy when the working collection is lost or damaged. One product can offer both capabilities, so the label on the app is less useful than understanding exactly what it preserves.

Microsoft’s OneDrive documentation makes the sync behavior clear: additions, changes, and deletions in the OneDrive folder are reflected online, and changes online are reflected on the computer. That is convenient when moving between devices. It also means an accidental deletion can travel with you. Two visible instances of a file are not necessarily two independently protected copies.

Recovery features help—with limits

Sync services can still provide valuable protection. OneDrive has a recycle bin, and Microsoft describes additional restore options, including rolling back an entire OneDrive for eligible Microsoft 365 subscribers. Those features have conditions and retention limits. Microsoft also says permanently deleted recycle-bin items cannot be restored through that route.

Before relying on a service, answer three questions: how far back can I go, what events can I recover from, and what happens if I lose access to the account? A feature that rescues a document deleted yesterday might not cover a mistake discovered months later. Check the documentation for your particular account and plan.

Look for a history you can restore

A versioned backup keeps earlier states rather than simply making another location match today’s files. Apple’s Time Machine is one example: it automatically backs up files to a configured storage device and maintains a history of backups. Apple notes that the oldest backups are deleted when the backup disk fills, so even a dedicated backup has a retention boundary.

Inspect the selected folders and the date of the last completed backup. Pay particular attention to cloud-only files: seeing a filename in a folder does not prove that its full contents are stored locally or included in another backup. Confirm coverage with the backup tool’s documentation and a restore exercise.

Separate the copies, then test one

The Canadian Centre for Cyber Security recommends the 3-2-1 approach: three copies in total, on two media types, with one copy offsite. It also recommends an offline backup and regular recovery tests. These choices address different failures: an offsite copy helps if equipment at home is lost, while a disconnected copy limits exposure to attacks on connected systems.

A practical starting point is to identify the files you cannot replace, set up an automatic backup, and add a separate recovery copy with appropriate protection. Choose a schedule based on how much recent work you could tolerate losing.

• Restore a harmless test file into a temporary folder, without overwriting the original.
• Open the restored file and check its contents and date.
• Record where the backup lives and how to unlock it; protect any recovery credentials.
• Repeat the check after changing devices, accounts, or backup settings.