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Building a Private OneDrive with Syncthing, Centered on NAS via Docker Desktop

If you want a self-hosted, cross-platform synchronization solution like OneDrive, Syncthing is a powerful tool. This guide walks through how I used Docker Desktop and a NAS as the central hub to keep documents synchronized across Windows, macOS, and other devices.

📦 What is Syncthing?​

Syncthing is an open-source, continuous file synchronization program. It synchronizes files between two or more computers in real time, safely protected from prying eyes.

🧩 System Structure​

  • NAS (QNAP / ZimaBoard / etc.): Runs the core Syncthing instance in Docker.
  • Windows PC & MacBook: Each runs Syncthing and syncs through the NAS.
  • Private network or Internet: All communication is peer-to-peer via QUIC/TCP/relay.

🐳 Deploying Syncthing on NAS via Docker Desktop​

On your NAS (or PC acting as central node), use Docker Desktop to run the container:

Docker Image​

linuxserver/syncthing:latest

Ports Mapping​

Container PortHost PortPurpose
21027/udp21027Local discovery broadcast
22000/tcp22000Main sync traffic via TCP
22000/udp22000Sync traffic via QUIC
8384/tcp8384Web GUI

You can map different ports if you like, but remember to forward or open them in your NAS/router firewall.

Volume Mounts​

Host PathContainer Path
E:\Docker\syncthing\config/config
E:\daisuke/data

Ensure both paths are granted permission in Docker Desktop → Settings → Resources → File sharing.

🛠️ First Launch Issues​

Common Errors & Fixes​

1. permission denied errors​

mkdir /run/s6-rc: permission denied

→ Make sure Docker Desktop has access to the folder (Windows: File sharing enabled + Admin privileges).

2. Folder path missing​

Error on folder "Windows-Documents": folder path missing

→ Check the folder path in Syncthing settings. Ensure the actual path exists and is shared with Docker.

3. setting permissions: operation not permitted​

→ This usually happens on Windows. Disable these in folder settings:

  • "Send Ownership"
  • "Sync Ownership"
  • "Send Extended Attributes"
  • "Sync Extended Attributes"

⚙️ Autostart Syncthing Container​

To make the container auto-start on reboot, use Docker Compose or set the --restart unless-stopped option in docker run.
Docker Desktop GUI doesn’t offer this toggle directly.

If you're using CLI:

docker run -d \
  --name=syncthing \
  --restart unless-stopped \
  -p 8384:8384 -p 22000:22000 -p 22000:22000/udp -p 21027:21027/udp \
  -v E:/Docker/syncthing/config:/config \
  -v E:/daisuke:/data \
  linuxserver/syncthing:latest

🧩 Sharing Strategy (Recommended Setup)​

  • Let NAS share folders to Windows and Mac.
  • On Syncthing GUI:
    • NAS adds folders.
    • Windows/Mac are just "receive & send" devices.
  • Only NAS should be shared with both endpoints; avoid direct sync between Mac and Windows to reduce conflict.

✅ Tips for Better Stability​

  • Use NTFS or ext4 for mounted folders, avoid FAT/exFAT.
  • Disable permission syncing on non-Linux hosts.
  • Use fixed folder paths and avoid renaming folders after setup.
  • Always check for .stfolder inside shared folders (used by Syncthing to mark valid sync).

🎉 Result​

Now I have a fully private, real-time, cross-device syncing system that works just like OneDrive — but it’s 100% under my control.

Happy syncing!

Written by daisuke — powered by NAS + Docker + Syncthing 🚀