What is mirror sync?

Mirror Sync is one of sync solutions in AOMEI Backupper to sync files from source directory to destination directory, just like basic sync and real-time sync. But this feature focuses on making files in the destination always exactly the same as source.

That’s to say, you can only add or modify files in source directory. If you do so in the destination, the newly added files in destination will be deleted and the modified files will be overwritten by files with the same name in the source, regardless of file size and modified time.

Why do you need mirror sync?

As you known, mirror sync makes an exact copy of files that can be treated as a backup, so you don’t need to worry about data loss. That can be one of the most important reason to mirror files or folders.

Meanwhile, this feature will delete extra files and overwrite files modified in the destination. To some extent, it prevents any unwanted or malicious changes, or virus attacks.

In addition, the synchronized files/folders are easy to access and check. Because they are all the same except the storage location,

How does mirror sync work?

So far, you may have a general understanding of mirror synchronization. Next, let's take a closer look at how it works.

During each synchronization, the source directory will directly compare with destination directory to find out the differences, then do as follow.

  • The files with the same name in the destination directory will be overwritten when it has difference size or the modification time is difference. It is the same even if the file size is larger or modification time is the latest.

  • The files in source directory but not in destination will be synchronized to destination.

  • The files in destination directory but not in source will be deleted from the destination.

Step by step guide: mirror folder with AOMEI Backupper Professional

AOMEI Backupper Professional, as the best file sync software, allows you to mirror folders in Windows 11/10/8/7/XP/Vista to any detected devices, such as local disk, external hard drive, flash drive, network drive, NAS, cloud storage like Google Drive, Microsoft OneDrive, etc.

Also, the sync process can be automatic, including daily, weekly, monthly, event triggers, USB plug in, so you can always have the latest files. It reduces the risk of data loss.

Then, without further ado, let’s get started. First of all, download AOMEI Backupper Professional and install it on your computer. Then, prepare a storage device to save your files. Here I choose a USB drive, because it’s very easy to carry and the price is affordable.

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Step 1. Launch this software, click Sync and Mirror Sync in turn.

Mirror Sync

Step 2. Name the task as per your need and click + Add Folder This PC to select the folders you want to mirror.

Add Folder

Step 3. Click where the arrow points and it will show you the drop-down menu. There are three options available:

  • Select a local path: in the pop-up window, click This PC and select your USB drive under Devices and drives.
  • Add Share or NAS Devices: it allows you to select a shared folder, network drive or NAS.
  • Select a cloud drive: you can choose cloud storage as the destination path, such as OneDrive, Google Drive and Dropbox.

Select USB

Step 4. Set schedule sync task to track changes continuously. Click Schedule Sync and select your priority. Here are 5 options you can choose from, including daily/weekly/monthly, event triggers and USB plug in.


◔ Daily/weekly/monthly sync is enough to keep track of changes if you don’t modify files very frequently. 
◔ “Event triggers” can help you do Windows mirror folder in a specific event, such as, user logon, user logoff, system startup and system shutdown. 
◔ “USB plug in” can help you sync files from or to USB flash drive automatically when the device is plugged in, even without opening the software manually. 
◔ At the bottom of schedule settings, you will see another option, “Wake the computer to run scheduled task”. It is helpful when you set the schedule sync task to off-peak hours, such as, midnight.

Step 5. Confirm everything is OK and click Start Sync to mirror files.

USB Mirror Sync

◔ Don’t modify the name of the source folder of a scheduled sync task, or the program cannot synchronize it anymore. 
◔ Don’t add new files to destination path or modify files in destination, because these files finally are either deleted or overwritten. 
◔ The single file over 4GB can’t be synchronized to FAT/FAT32 partition, because the file size in FAT/FAT32 partition is limited to 4GB. 
◔ The core of mirror sync is one-way file sync. AOMEI Backupper still supports two-way file sync to track changes in both source directory and destination directory. 
◔ If you modify files very frequently or work in a team, it’s suggested to use “Real-Time Sync”. This feature will keep track of changes in real-time and sync files immediately when detected.

Actually, AOMEI Backupper is still professional backup and restore software. It offers System Backup, Disk/Partition Backup, File Backup and Cloud Backup to meet your different needs. Don't hesitate to try it out!