What Is Sync Software and How Does It Differ from Backup and Cloning?

Sync software keeps two locations matching each other — when a file changes on one side, the change is applied to the other, either in real time or on a schedule. It is the right tool when you want the same working files available in more than one place, such as a laptop folder and an external drive, or a PC folder and a NAS. It is not the right tool for disaster recovery on its own, because sync also copies deletions and mistakes. Backup software keeps recoverable versions so you can go back in time; cloning software copies an entire disk or operating system for migration. If your goal is "the same files in two places," choose sync. If your goal is "get my data back after something goes wrong," choose backup. Many people run both.

What sync software actually does

Sync software compares a source and a destination and makes the destination match the source (one-way sync) or makes both sides match each other (two-way sync). Depending on the tool, it can run on a schedule, on an event (such as file change or logon), or continuously.

AOMEI Backupper, for example, is described on its product page as Windows backup, clone and sync software, and its file sync feature is listed as working "from source directory to destination directory" — a one-way direction. Supported destinations named on the page include local or external drive, NAS, and network share. The same page lists a Mac counterpart (AOMEI Backupper Mac) as "standalone Mac backup and sync software," so the platform question matters: Windows and Mac editions are separate products.

One-way vs two-way sync

Two-way sync is more convenient and more dangerous: a file deleted by mistake on one side can be deleted on the other before you notice. One-way sync limits that risk to the destination but still overwrites destination changes.

How sync differs from backup

The core difference is versioning and direction.

• Backup makes a copy you can restore from, and good backup tools keep multiple points in time (full plus incremental or differential). If a file is corrupted or deleted today, you can restore yesterday's version.
• Sync makes the two locations equal. If a file is deleted or encrypted by ransomware on the source, the deletion or the encrypted file is propagated. There is usually no "go back to last Tuesday" unless the tool also keeps versions.

This is why sync is often described as convenience, not protection. A synced copy on an external drive is not a substitute for a backup if the sync runs after the damage is done. A practical pattern is: sync for day-to-day access, backup for recovery, and keep at least one copy offline or disconnected so it cannot be overwritten.

How sync differs from cloning

Cloning copies an entire disk or partition — including the operating system, boot records, and installed applications — so the target can boot and run as a replacement. It is used for disk upgrades, OS migration to an SSD, or standing up identical machines.

Sync operates on selected files and folders, not on the disk structure. It does not make a drive bootable and does not move your installed programs. If your goal is "move Windows to a new SSD," that is cloning or migration, not sync. If your goal is "keep my Documents folder identical on two drives," that is sync.

What to check before choosing sync software

• Direction: Does it support one-way, two-way, or both? Match this to your risk tolerance.
• Trigger: Manual, scheduled, real-time, or event-triggered (file change, logon). Real-time is convenient but propagates mistakes fastest.
• Destinations: Local drive, external drive, NAS, network share, or cloud. Confirm your target is supported before committing.
• Platform: Windows and Mac editions are often separate products with different feature sets. Check the edition that matches your machine.
• Versioning or recycle bin: Does the tool keep old versions or a recoverable trash on the destination? This is what saves you from a mirrored deletion.
• Conflict handling: For two-way sync, how does it resolve a file changed on both sides at once?
• Edition fit: Vendors often split home, professional, workstation, and server editions. AOMEI's page lists Standard (free), Professional, Workstation, Server, Technician, and Technician Plus editions, and points to an edition comparison for differences. Check the comparison rather than assuming features carry across tiers.

Common failure modes

• Mirrored deletion: You delete a folder to "clean up," sync runs, and the copy is gone too. Mitigate with versioning, a recycle bin on the destination, or a delayed/one-way schedule.
• Sync conflicts: Two-way sync with edits on both sides can produce duplicate or conflicted files. Know how your tool names and resolves them.
• Treating sync as backup: A synced copy is not a recovery point. If ransomware or a bad edit reaches the source before the sync, both sides are affected.
• Wrong direction: Setting up two-way sync when you meant to protect a source folder means the destination can overwrite the source.

A quick way to decide

Ask what you need to survive:

• "I need the same files on two devices." Sync.
• "I need to recover a file I deleted or corrupted." Backup with versioning.
• "I need to move my whole system to a new disk." Cloning or OS migration.
• "I need all three." Run backup and cloning as your safety net, and add sync only for the folders where having two live copies genuinely helps — and keep one backup copy offline.