This article will guide you through the process of backing up data from your Mac to Synology NAS using Apple’s Time Machine, a backup utility included with macOS 10.5 and later.

Set up DSM to support Time Machine

1. Create a shared folder for Time Machine backup.
   1. Sign in to DSM using an administrator account.
   2. Go to Control Panel > Shared Folder and click Create.
   3. Enter a name for the shared folder (such as “Time Machine Folder”) and select a location (if multiple volumes exist). In this example, we chose Volume 1.
      
   4. We do not recommend you to enable the recycle bin feature or to use encrypted shared folders as your Time Machine destination. Click Next.¹
   5. Configure advanced settings for the shared folder as needed and then click Next.
   6. Continue through the wizard to complete the process.
2. Create a user for Time Machine and set a quota limit.
   1. Do one of the following depending on your DSM version:
      • DSM 7.0 and above: Go to Control Panel > User & Group > User and click Create.
      • DSM 6.2 and below: Go to Control Panel > User, and click Create.
   2. Enter a username and specify a password. Continue through the wizard.
   3. On the Assign shared folders permissions page, assign Read/Write permissions for Time Machine Folder.
      
   4. On the Assign user quota page, enter a value you prefer in the User Quota field for the Time Machine folder and select a unit from the drop-down menu. After specifying a quota, click Next.^2 3
      
   5. On the Assign application permissions page, tick the Allow checkbox for AFP or SMB and click Next. Those using DSM 6.2 and below can skip this step.
      
   6. Continue through the next prompts to complete the process.
3. Set the shared folder as Time Machine’s backup target.
   1. Go to Control Panel > File Services.
   2. Do the following depending on your DSM version:
      • DSM 7.0 and above: For SMB, go to the SMB tab and tick the Enable SMB service checkbox.⁴ For AFP, go to the AFP tab and tick the Enable AFP service checkbox.
      • DSM 6.2 and below: Go to the SMB/AFP/NFS tab. Tick the Enable SMB service checkbox for SMB⁴, or tick the Enable AFP service checkbox for AFP.
   3. Go to the Advanced tab and tick the Enable Bonjour Time Machine broadcast via SMB or Enable Bonjour Time Machine broadcast via AFP checkbox. Then, click on the Set Time Machine Folders button.
   4. Choose the shared folder that you just created from the Time Machine menu and save your settings.

Perform Time Machine Backup to your Synology NAS

1. On your Mac, open System Preferences from the Dock, and click Time Machine.
2. Click Select Backup Disk.
   
3. Choose the shared folder that you created (i.e., Time Machine Folder on “Server name of your Synology NAS.local”) and click Use Disk.
4. The system will prompt you to provide your account credentials. Enter the username and password for the user that you have just created and click Connect.
5. Time Machine will soon start backing up your data.