Your show files,
mirrored in real time.
ShowSync keeps a live, one-way copy of your show folder on a second Mac — so if your main Mac ever fails mid-event, an up-to-date backup is already waiting. This guide covers setup, pairing, syncing, and licensing.
What ShowSync does
ShowSync runs quietly in the menu bar and mirrors a folder from one Mac (the Main) to another (the Backup) over your local network. It is built for live production, where a second copy of your cues, sets, recordings, or project files can save a show.
One-way, by design
Files only ever travel from Main to Backup. The Backup receives and never sends back, so your working copy is never overwritten by the mirror.
Additive and safe
Transfers are delta-based (only changes move) and additive. A write-test runs before each sync, with a safe-folder fallback if the destination drive isn't ready.
Calm and quiet
It sits in the menu bar using almost no resources, works on events rather than constant polling, and shows honest status at a glance.
Encrypted on the wire
Every transfer runs over SSH (AES-encrypted) with key-based trust and a human-confirmed pairing step — no passwords stored.
Requirements
- Two Macs running macOS 13 (Ventura) or later — one acts as Main, one as Backup.
- Both Macs on the same local network (wired is recommended for shows).
- On the Backup Mac, Remote Login must be enabled (System Settings → General → Sharing → Remote Login). ShowSync will prompt you if it's off.
- An internet connection at first run to start a trial or activate a license. After activation, ShowSync verifies your license offline — no internet needed at show time.
A single license covers two machines. The Backup edition (receive-only) is always free, so you only need a license on the Mac that sends.
Quick start
If you just want to get running, this is the short path. Each step is expanded later in the guide.
- Install ShowSync on both Macs. It appears in the menu bar — click the icon to open it.
- On the Backup Mac, turn on Remote Login and set its role to Backup (Settings → Connection → Role → Switch to Backup).
- On the Main Mac, start a trial or activate a license (Settings → License). Until then, the Main Mac runs in free Backup-only mode.
- Pair the two Macs. On the Main Mac, choose the Backup under Discovery and click Pair Automatically. Confirm the matching code on the Backup.
- Choose your source folder on the Main Mac (Choose…).
- Click Sync Now. Your files mirror to ~/Sync on the Backup.
Main & Backup roles
Every Mac running ShowSync is either a Main or a Backup.
| Role | What it does | Menu-bar icon |
|---|---|---|
| Main | Sends files — the source machine, the one you work on. This is the licensed role. | Up arrow in a circle |
| Backup | Receives files into ~/Sync. Receive-only, and always free. | Down arrow in a circle |
To change a Mac's role, open Settings → Connection → Role and click Switch to Backup or Switch to Main. You'll be asked to confirm — "The app will restart in the new role."
The Switch to Main option only appears when the Mac has an active trial or license. Without one, the Mac stays in free Backup-only mode (see Backup-only mode).
Prepare the Backup Mac
The Backup Mac receives files, so it needs Remote Login enabled and its role set to Backup.
- Enable Remote Login. Open System Settings → General → Sharing → turn on Remote Login. If ShowSync needs it and it's off, you'll see "Remote Login Required — ShowSync needs Remote Login enabled on this Mac to receive files." with a button to open System Settings.
- Set the role to Backup. Settings → Connection → Role → Switch to Backup. The app restarts as a Backup.
- Confirm it's listening. The Backup popover shows Network Discovery, This Mac's IP, and Backup User. When files arrive you'll see Receiving….
Incoming files are written to ~/Sync by default. You can change this to another folder in your home directory or on an external drive — but not Documents, Desktop, or Downloads, which macOS protects from network writes.
Pairing the two Macs
Pairing establishes a trusted, encrypted connection between Main and Backup. It only has to be done once per pair.
Automatic pairing (recommended)
- On the Main Mac, open Settings → Connection. Leave Discovery on Automatic.
- Your Backup Mac appears in the discovery list. Select it, then click Pair Automatically.
- ShowSync shows Pairing…, then a request appears on the Backup Mac titled "Pairing Request".
- On the Backup, check the verification code matches the one under "This Mac's Verification Code" on the Main, then click Trust.
- The Main shows Paired with [name] and the Secure Connection indicator turns to Connected.
The verification code is your security check. Only click Trust when the code on the Backup matches the code shown on the Main's Settings screen — that confirms you're pairing with the right machine.
Manual setup
If the Backup doesn't appear automatically, switch Discovery to Manual and click Set Up Manually. You'll be asked to enter the Backup's username and IP address (both shown on the Backup Mac's popover), then Set Up Secure Connection.
If you ever need to unpair
In Settings, Forget This Backup (on the Main) or Forget Paired Main (on the Backup) clears the pairing. You'll be asked to confirm. To re-pair, run automatic pairing again.
Choosing folders
On the Main — the source
Under Settings → Connection → Source, click Choose… and pick the folder you want mirrored (your show folder, project, recordings, etc.). Until a source is set, ShowSync shows "Choose a source folder."
On the Backup — the destination
Files arrive in ~/Sync by default. The destination is shown under Destination; use Change and Confirm Destination if you need a different location.
macOS protects Documents, Desktop, and Downloads, so the Backup can't write there. Choose a folder inside your home directory (the default ~/Sync works out of the box) or on an external drive. If you pick a protected folder, ShowSync tells you: "This Folder Can't Receive Files Over the Network — Documents, Desktop, and Downloads are protected by macOS. Please choose another folder, like a folder in your home directory or an external drive."
Syncing files
Open the Main Mac's popover and click Sync Now. ShowSync copies any new or changed files to the Backup. Because transfers are delta-based, the first sync moves everything and later syncs are near-instant.
While a sync runs you'll see progress like Syncing… 64% · 2.1 of 3.3 GB, and you can stop it with Cancel Sync. When it finishes, Last sync updates with the time, file count, and size.
Turn on Check files before sync (Settings → Behaviour) to preview what would change. The Sync button then reads Check Files — a dry run that reports differences without copying.
Auto Sync & Push Sync
Two options in Settings → Behaviour keep the Backup current without you clicking each time:
Auto Sync
Mirrors on a schedule. Pick from preset intervals — 30 seconds, 5, 10, 15, or 30 minutes, or 1 hour — or set a custom interval of 1–360 minutes and click Apply. A · Auto badge appears in the popover when it's on.
Push Sync
Mirrors automatically whenever files in the source folder change. ShowSync watches the folder and, once changes settle (go quiet), runs a sync — so it doesn't fire mid-copy. You choose how long to wait for things to settle: a debounce of 5, 10, or 30 seconds, or 1 minute, or a custom delay of 5–300 seconds. Ideal during an active show when files are being added continuously.
You can also trigger a sync from anywhere with the global shortcut ⌃ ⌥ ⌘ S (toggle it under Settings → Behaviour → Options).
Version History
When enabled (Settings → Behaviour), ShowSync keeps previous copies of files on the Backup, so an overwrite never loses the older version.
Before each sync, ShowSync works out which files are about to be replaced and saves the existing Backup copy alongside the new one, with a timestamped name like report~sync-v~2026-06-16_14-30-05.pdf. The new version then takes the original's place, and the older copy stays in the same folder as a dated twin.
You choose how many versions to keep per file — 3, 5, 10, 15, or 20 (default 3). Once the limit is reached, ShowSync removes the oldest copies after each sync. There's no time limit — only the count matters.
What it covers
Version History applies to files that are changed or overwritten. Because ShowSync is additive — it never deletes files on the Backup to match the Main — files you delete on the Main are not removed or versioned on the Backup; they simply remain. This keeps your Backup safe: a deletion on the Main can never wipe files from the mirror.
Versioning runs within each sync and never delays or blocks a backup.
Verifying a backup
To confirm the Backup is a faithful copy, click Verify on the Main (or Verify Backup on the Backup). ShowSync checks the source against the Backup and reports one of:
Fast vs Deep verify
You can choose how thorough Verify is, under Settings → Behaviour → Verify:
Deep (default)
Checks every file's contents with a checksum — a true byte-for-byte comparison. The most thorough check; it catches a file that's the right size but has changed or become corrupted. Best before a critical show. On very large files it takes longer, because every byte is read on both Macs.
Fast
Checks each file's size and modification date only — not its contents. Near-instant even on very large files. Ideal for a quick "is everything there and the right size?" check when you're working with large media and don't need a full content comparison.
Leave it on Deep for normal show files — it's thorough and fast enough when files aren't huge. Switch to Fast when you have very large files (multi-gigabyte media) and just want to confirm they're all present quickly. The result wording tells you which check ran, so you always know what was confirmed.
Every sync already verifies file integrity as it transfers (and re-sends anything that doesn't arrive cleanly), so a successfully synced file is checked at the moment it's copied. Deep verify additionally re-confirms the contents later — useful for catching changes or drive issues that happen after a sync.
Reading the status
The menu-bar icon colour tells you the state at a glance:
The popover also shows connection details (Backup IP, user, folder, this Mac's IP), the last sync summary, and the Secure Connection indicator (Connected / Not Connected).
Trial & license
The full Main (sending) capability is unlocked by a 14-day free trial or a purchased license. Open Settings → License.
Starting a free trial
Click Start free trial to begin a 14-day trial on this Mac, or paste a key you've been given into Enter license key and click Activate. After activating, you'll see "Activated — relaunch to enable Main mode." — quit and reopen ShowSync to switch into Main.
What the status line means
Two machines per license
One license activates ShowSync on up to two Macs. If you try to activate a third, you'll see "Already active on the maximum 2 Macs."
Activation needs the internet once. After that, ShowSync verifies your license offline — so it keeps working on isolated show networks with no internet access.
Backup-only mode
When a Mac has no active trial or license, ShowSync runs in Backup-only mode: it can still receive files (so a free machine is always useful as a Backup), but the Main sending features are hidden. You'll see the note "Backup-only — activate a license to enable Main mode."
Start a trial or activate a license, relaunch, and the full Main capability returns. Your saved role and settings are never lost while in Backup-only mode.
Settings reference
Settings are grouped into five sections, opened from the gear icon in the popover.
| Section | What's inside |
|---|---|
| Connection | Role (Main/Backup), Discovery (Automatic/Manual), Source folder, Destination, Pairing, Network Interface. |
| Identity & Trust | This Mac's identity and verification, change Backup name, Secure Connection status, Forget This Backup / Forget Paired Main. |
| Behaviour | Auto Sync & interval, Push Sync, Version History, Verify mode (Fast / Deep), Check files before sync, Launch at Login, global shortcut, where ShowSync appears (Menu Bar / Menu Bar & Dock). |
| License | Trial & activation, license status, days remaining. |
| About | Version, credits, and Check for Updates. |
Reset to Defaults (with a confirmation) returns settings to their original state. It does not delete your files.
Updates
Under Settings → About, click Check for Updates. ShowSync checks for a newer version and reports one of:
Network & security
For best performance and security, run ShowSync on a dedicated, hardwired network. All transfers are encrypted (AES, over SSH) with key-based trust and a human-confirmed pairing step — no passwords are stored.
ShowSync uses ShowNetwork, Remember Live's interface-binding technology, to keep show traffic on the network interface you choose — so your sync stays on your dedicated show network. Pick the interface under Settings → Connection → Network Interface.
Why wired
A dedicated cabled network gives you the fastest, most reliable transfers — often close to full gigabit speed — and keeps show traffic isolated from other devices.
One-way trust
Trust flows in one direction (Main → Backup). The Backup can only receive, never reach back into the Main.
Troubleshooting
The Backup doesn't appear when pairing
Confirm both Macs are on the same network and the Backup has Remote Login enabled. If it still doesn't show, switch Discovery to Manual and enter the Backup's username and IP (both on the Backup's popover).
"Backup not reachable on selected network"
The Backup can't be reached on the chosen network interface. Check cabling/Wi-Fi, and confirm the Network Interface in Settings → Connection matches the network the Backup is on.
Sync won't start
ShowSync tells you why inline — common reasons: "Choose a source folder," "No Backup selected," "No Backup user set," "Connection not yet set up," or "Backup not reachable on selected network." Resolve the stated item and try again.
"Remote Login Required" on the Backup
Open System Settings → General → Sharing and turn on Remote Login, then return to ShowSync.
"Already active on the maximum 2 Macs"
Your license already covers two machines. To move it to a different Mac, deactivate it on one of the current machines first, or contact Remember Live.
"Couldn't reach the licensing server"
Activation needs internet once. Connect to the internet to activate or start a trial; afterwards ShowSync works offline.
"This Folder Can't Receive Files Over the Network"
You chose a destination macOS protects (Documents, Desktop, or Downloads). Pick a folder inside your home directory (such as the default ~/Sync) or on an external drive instead.
The Main Mac only shows Backup features
It's in Backup-only mode — start a trial or activate a license in Settings → License, then relaunch.