How to Use macOS Time Machine to Backup to a Network Attached Storage (NAS) Drive

Time Machine is the brilliant, built-in backup solution for macOS. It takes hourly snapshots of your entire system, allowing you to recover a single deleted file or restore your entire Mac to a brand-new machine. While most users plug in an external USB hard drive, doing so defeats the purpose for a MacBook that frequently moves around. By configuring Time Machine to back up over Wi-Fi to a Network Attached Storage (NAS) device (like a Synology or QNAP), your Mac will back up silently and automatically the moment you connect to your home or office network.

Step 1: Prepare the NAS Drive

Before touching your Mac, you must configure your NAS to advertise itself as a Time Machine destination. (The exact steps vary by manufacturer, but the principles are identical).

1. Log in to your NAS administrative interface via a web browser.
2. Create a Shared Folder: Create a new shared folder specifically dedicated to backups (e.g., named “MacBackup”).
3. Create a Dedicated User: Do not use your primary NAS admin account. Create a new user (e.g., “tm_user”) and assign it a strong password. Grant this user Read/Write permissions only to the “MacBackup” folder.
4. Set a Quota (Crucial): Time Machine is designed to consume all available space until the drive is full, at which point it deletes the oldest backups. If you don’t set a storage quota on the NAS user or folder (e.g., limiting it to 2TB), Time Machine will eventually consume your entire NAS array, leaving no room for your other files.
5. Enable the Protocol: Ensure that the SMB (Server Message Block) file-sharing protocol is enabled, and specifically check the box to “Enable Bonjour Time Machine broadcast via SMB.” (Older NAS units relied on the deprecated AFP protocol; modern macOS versions strongly prefer SMB).

Step 2: Connect the Mac to the NAS

Now, move to the Mac you want to back up.

1. Open Finder.
2. From the top menu bar, click Go > Connect to Server… (or press Cmd + K).
3. Type smb:// followed by the IP address or hostname of your NAS (e.g., smb://192.168.1.50). Click Connect.
4. When prompted, enter the credentials for the dedicated Time Machine user (“tm_user”) you created in Step 1. Check the box to Remember this password in my keychain.
5. Select the “MacBackup” volume to mount it.

Step 3: Select the Backup Disk in Time Machine

1. Click the Apple menu () and select System Settings.
2. Navigate to General > Time Machine.
3. Click the Add Backup Disk… button.
4. Because you enabled the Bonjour broadcast on the NAS, the “MacBackup” shared folder should appear in the list automatically. Select it and click Set Up Disk.
5. You will be prompted to enter the NAS username and password one final time to authorize Time Machine.

Step 4: Enable Encryption

Time Machine will ask if you want to encrypt the backup. Always choose yes when backing up over a network. If a thief steals your NAS, they can easily extract all your Mac’s data unless the Time Machine bundle is encrypted. Enter a strong backup password (separate from your Mac login password) and store it in a password manager.

Once you click Done, the initial backup will begin. This first run can take several hours (or days, depending on your Wi-Fi speed), but all subsequent hourly backups will only transfer the tiny changes made to your files, executing invisibly in the background.