MacOS’s Time Machine backup utility lets you back up your entire computer to an external hard drive, but you can also back up to a NAS that’s on your local network. Here’s how to do it.

We’ve shown you how to set up Time Machine on your Mac. It’s pretty easy to do when you’re just backing up to an external hard drive that’s connected directly to your computer. However, if you’d rather use your Synology NAS that’s connected to your local network, there’s a bit more work to do (but it’s still pretty easy).

Step One: Create a Share Specifically for Time Machine

The first thing you’ll need to do is create a separate shared folder on your NAS that’s specifically for Time Machine backups. To do this, fire up DiskStation Manager and open up the Control Panel.

Click the “Shared Folder” item.

Open the “Create” dropdown menu, and then click the “Create” command.

Give the shared folder a name (like “Time Machine”) and then disable the Recycle Bin (you won’t need this for Time Machine backups). Hit “Next” to continue.

On the next screen, you can enable encryption for your Time Machine backups if you want. If you choose to do this, it’s better for your Synology NAS to handle it, rather than macOS, as that will free up resources on your computer.

Turn on the “Enable Shared Folder Quota” option. This places a maximum capacity on the shared folder so that Time Machine doesn’t continue to create more and more backups until it fills up the entire NAS.

Below that, enter a storage size that’s about three times the size of your Mac’s storage capacity (e.g. if your Mac has 250 GB of storage space, make the storage size 750 GB). You can enter whatever you want, but I find this to be the sweet spot that includes a longer history of backups without getting too crazy on storage space.

On the next screen, hit the “Apply” button to confirm the settings.

Next, you’ll set user permissions for the shared folder. The defaults are pretty good, so you’re safe just going ahead and hitting the “OK” button. You can create a new user specifically for the Time Machine backup with a different password and everything, but it’s not required.

You’ll now see your new Time Machine shared folder in the list.

Step Two: Enable Time Machine Access for the Share

Now that you’ve created the shared folder, you need to enable a couple of features so that Time Machine can successfully back up to it. To get started with this, click “File Services” in the left-hand sidebar of the NAS control panel.

On the “SMB/AFP/NFS” tab, enable the “Enable SMB Service” option. If you have macOS El Capitan or older, you’ll want to use AFP instead by scrolling down a bit and ticking the “Enable AFP Service” check box.

Next, witch over to the “Advanced” tab, and then tick the “Enable Bonjour Time Machine broadcast via SMB” option (or AFP if you’re on an older version of macOS).

After that, click the “Set Time Machine Folders” button.

Place a check next to the Time Machine shared folder that you created earlier, and then hit the “Apply” button.

Click “Yes” when the pop-up appears.

Step Three: Connect Your Mac to Your NAS

If you’ve already been using your NAS for other things, it’s likely that your Mac is already connected to it. If it is, skip to the next section. If it’s not already connected, follow the steps below.

On your Mac desktop, open the “Go” menu, and then select the “Connect to Server” command.

In the text box, type¬†smb:// followed by the name of your NAS or its local IP address. Hit “Connect” to continue. You may be prompted to enter the log in credentials for the NAS.

Step Four: Set Time Machine to Back Up to Your NAS

When your Mac is connected to your NAS, open up System Preferences and select the “Time Machine” option.

Click the “Select Disk” button.

Select the shared folder that you created for your Time Machine backups, and then click the “Use Disk” button.

If you had a previous storage drive linked to Time Machine, you’ll get a pop-up asking you if you want to use both disks or replace the old one with your new disk. Choose the “Replace” option.

You may be prompted to enter your NAS’s log in credentials again before you can continue, but when that’s done, you’ll be all set.

Your Mac will now automatically back up to your Synology NAS.