OKTOID OneWaySync
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OneWaySync for Mac

Your folders, mirrored one way.

Exact mirrors of your folders on external drives, NAS, USB sticks or anywhere else. The source is only ever read, and after the first copy only new and changed files are transferred.

Get it on the Mac App Store How it works

For macOS 11 or later · Made by Oktoid since 2011

How it works

Drag, drag, START.

Each setup, called a slot, has its own source, destination and options, and you can make as many as you want.

  1. Drag in a source

    Any folder. Or click Use Photos Library or Use Music Library to connect your libraries.

  2. Drag in a destination

    An external drive, a NAS, a USB stick or any other folder.

  3. Press START

    The first sync copies everything. After that, only new and changed files are transferred.

Mirror or keep

An exact mirror, or everything, ever.

Delete a file at the source, and you decide what happens to its copy. Flip the switch and see.

Source: Documents

  • Budget 2026.numbers
  • Logo final.png
  • Old draft.pagesdeleted
  • Notes.txt
  • Taxes 2025.pdf

Destination: Backup

  • Budget 2026.numbers
  • Logo final.png
  • Old draft.pagesremoved
  • Notes.txt
  • Taxes 2025.pdf

Both sides match.

  • Mix sources. Point several slots at the same destination to combine folders in one place.
  • Hidden files and labels. Copies hidden files if you want them, and keeps Finder label colours.
  • Renamed or moved? OneWaySync follows its folders even when they are renamed or moved.
  • Only what changed. After the first copy, each sync transfers only new and changed files.

Photos and Music too

Your libraries, in plain folders.

Click Use Photos Library or Use Music Library, and OneWaySync copies your photos, videos and songs into neatly organized folders that Windows, TVs, media players and any backup tool can read. You design the folders with simple tags. Try it:

Start from
File path
Add a folder level

In the app you drag tags like these into the File Path field, mixed with any text you like.

    • Edited or originals. Copy photos as you see them in Photos, or the untouched originals.
    • JPEG and size. Convert photos to JPEG, and resize them to a maximum size.
    • Playlists as folders. Songs, music videos and playlists, each with its own folder layout.
    • Old libraries welcome. iPhoto and iTunes libraries from older Macs are still read directly.

    Set it and forget it

    Backups that run themselves.

    Scheduled syncs

    Weekly on the days you pick, or repeating every few minutes.

    Queue them up

    Run slots one after another, or several at the same time.

    When it’s all done

    Quit, sleep, shut down, or run a script of your own.

    Safe to cancel

    Stop at any time. The next sync continues right where it stopped.

    Logs and colours

    Every operation can go to a log file, and each slot’s colour tells you how it went.

    • Syncing
    • Synced
    • Errors
    • Cancelled

    Fully scriptable

    Drive it with AppleScript. This syncs slot 1, then slots 2 and 3 one after another:

    tell application "OneWaySync"
	resume slot 1
	queue slot 2
	queue slot 3
end tell

    As many slots as you need

    Every slot has its own folders and options, ready at the press of a button.

    FAQ

    Good questions.

    Is my source folder or library ever changed?

    Never. Sources are only read; files are copied out of them.

    What happens when I delete files at the source?

    Your choice. With Delete on Destination on, their copies are removed on the next sync, keeping a perfect mirror. Leave it off to keep everything that was ever copied.

    My photos are in iCloud. Does this work?

    Yes. If Optimize Mac Storage is on, photos are downloaded automatically as they are copied.

    Is it safe to cancel a sync?

    Yes, at any time. The next sync continues right where it stopped.

    What do the slot colours mean?

    Yellow while a slot is syncing, green when it finished, red when there were errors, and magenta when you cancelled it. Turn on Write Log to see every detail.

    OneWaySync, Sync for iPhoto or Sync for iTunes?

    OneWaySync syncs any folder, plus your Photos and Music libraries. Sync for iPhoto or Photos and Sync for iTunes are each made for one library, with 14 slots ready to go.

    What do I need?

    A Mac with macOS 11 or later.

    The Sync family

    Three apps, one way.

    OneWaySyncAny folder, plus your Photos and Music libraries.You’re here Sync for iPhoto or PhotosYour photo library, in plain folders.Learn more → Sync for iTunesYour music library, in plain folders.Learn more →

    Set it up once. Sync for good.

    OneWaySync is on the Mac App Store, for macOS 11 or later.

    Get OneWaySync