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How to back up a Mac to a Synology NAS

Two ways to point a Synology at your Mac's files: Apple's built-in Time Machine, or a continuous mirror. Here's how to set up the NAS side, mount the share, and configure either — or both.

Updated August 9, 2026. Menu labels vary by DSM version — the steps below describe the general flow.

Set up the Synology side

Before your Mac can back up to a Synology, the NAS needs a place to put the files and a login with the right permissions. Do this once, from DSM (Synology's admin interface), in a web browser:

1. Create a dedicated shared folder. In DSM's Control Panel, under Shared Folder, create a new shared folder just for backups — one per Mac, or one per person, if more than one household or office member needs their own destination. Keeping backups in their own folder, separate from anything else on the NAS, makes permissions and cleanup simpler later.
2. Create or reuse a Synology user account. In Control Panel, under User & Group, either create a dedicated account for backups or use an existing one — either way, scope its permissions on the shared folder to read/write rather than backing up as the main admin account.
3. Confirm SMB is enabled. In Control Panel, under File Services, make sure the SMB service is turned on and that SMB3 is available. SMB is the protocol both Time Machine and a mirror tool like ThirdCopy use to reach the share from your Mac.
4. If Time Machine is the goal, turn that on too. DSM has a dedicated Time Machine option for shared folders in Control Panel — enabling it, either at folder creation or afterward, is what makes the share show up as a valid destination in macOS.

Mount the share on your Mac

With the Synology side set up, connect to it from the Mac that's going to back up:

1. In Finder, press Cmd+K (or go to Go → Connect to Server).
2. Enter smb:// followed by your Synology's IP address or local hostname, then a slash and the shared folder name — for example smb://192.168.1.20/MacBackups.
3. Sign in with the Synology user account, and save the password to your keychain so the Mac can reconnect without asking every time.
4. Once it's been mounted at least once, the share should also show up under Finder's Network sidebar via Bonjour discovery — useful for reconnecting later without re-typing the address.

Option A: Time Machine to your Synology

If your goal is Apple's own versioned backup: open System Settings → General → Time Machine → Add Backup Disk, and select the Synology share from the list. It only appears here if you enabled the Time Machine option on that shared folder in DSM first — that's the step people most often miss.

One protocol note worth acting on now rather than later: Time Machine backup over the older AFP protocol is being phased out by Apple, which has said it won't be supported starting with macOS 27. If you're setting up a Synology today, make sure the connection is over SMB — current DSM versions default to SMB for Time Machine shares, but it's worth confirming rather than assuming, especially on an older NAS that's been running the same configuration for years.

Option B: a continuous mirror with ThirdCopy

If what you actually want is a current, browsable copy of your files on the NAS — not a special backup-disk container you can only get into through Time Machine's interface — a mirror tool is the simpler match. ThirdCopy's setup is three steps, pointed at the Synology share you already mounted above:

1. Pick folders. Choose what to back up — Documents, Desktop, and Pictures cover most people's irreplaceable files, but you can add or remove folders freely.
2. Pick the destination. Point ThirdCopy at the mounted Synology share. It writes into its own subfolder there, so it's never sharing a folder root with anything else.
3. Pick a schedule. Continuous is the default — ThirdCopy watches your chosen folders and backs up shortly after something changes. Hourly, daily, weekly, and manual schedules are available too, including an option to back up specifically when the destination connects.

That last option matters more on a NAS than it sounds like it should. Synology units commonly run their own drive hibernation schedules to save power and reduce wear, so the NAS you're backing up to won't always be instantly awake and reachable. ThirdCopy handles this by skipping a scheduled or continuous run when the Synology isn't reachable, rather than reporting it as a failure, then catching up automatically as soon as the share reconnects — including after the NAS wakes from hibernation.

Why not both?

Time Machine and a mirror tool solve different problems, and a Synology has room for both. Time Machine's version history is what you want when you need to recover a file the way it looked three weeks ago, or roll back an entire Mac after something goes badly wrong — that's a job Time Machine is genuinely good at, and it's free. A mirror keeps a plain, current copy of the folders you care about most — no restore wizard, no sparse bundle to mount, just files you can open from any device on the network right now. Pointing both at the same Synology, into separate shared folders, costs nothing but a little disk space and covers more ground than either one alone.

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See also: does Time Machine work with a NAS? · ThirdCopy vs. ChronoSync · backing up a Mac to a QNAP NAS