guide · static export
Software

Keep Two Folders in Sync With Syncthing

Two PCs, one folder, no cloud account. Syncthing syncs directly over the network or the internet, and versioning protects you from your own deletions.

by@guidox updated:10/30/26 time:25 min level:Intermediate tested on:Windows 11 24H2, Syncthing 1.29 works on:Windows 10, Windows 11, Linux, macOS tools:Syncthing
TL;DR

Install **Syncthing** on both machines, pair them with the **device ID** and share the folder with **send and receive** mode. Turn on **simple file versioning** before the first sync.

Before you start

Requirements

  • Syncthing on both machines (SyncTrayzor on Windows is easier)
  • Both devices on the same network or with a relay available
  • The folder path on each side
Step by step

Instructions

01

Install and open the web UI

Install Syncthing, then open http://127.0.0.1:8384 on the machine. Everything is configured there - there is no separate desktop window.

http://127.0.0.1:8384
02

Set a GUI password

Under **Actions > Settings > GUI** set a username and password. The web UI is reachable from the network by default, and an open control panel is an open folder.

⚠ warningBind the GUI to 127.0.0.1 if you never need to reach it from another device.
03

Pair the two devices

On the first machine open **Actions > Show ID**, copy it and add it on the second machine with **Add Remote Device**. Accept the confirmation on the first side.

04

Share the folder

Add the folder on one side, set its type to **Send & Receive**, then share it with the other device. The second machine asks where to put it - use a path that is not inside another synced folder.

Folder type: Send & Receive
Rescan interval: 3600 s
tipA one-way mirror is Send Only on the source and Receive Only on the target. Use that for backups, not for editing on both sides.
05

Turn on versioning

In the folder settings enable **Simple File Versioning** with a few versions. Without it a delete on one machine becomes a delete on both within seconds.

Versioning: Simple File Versioning
Keep: 5 versions
⚠ warningVersioning stores old copies inside .stversions next to the folder. Budget the space.
06

Run it at login

Install it as a service or use SyncTrayzor's autostart so the sync runs before you log in. A sync client that starts when you remember to open it is not a sync.

Troubleshooting

Common issues

The devices never connect

Both are offline, or the firewall blocks port 22000. Check the device list for Last Seen and allow Syncthing on private networks.

Sync is stuck at 95 percent

A file is open on the other side or a path exceeds the Windows limit. Check the failed items list in the folder panel.

Everything got deleted on both sides

Versioning was off. Restore from .stversions if it exists, otherwise from your backup - this is why the backup guide exists.

The folder shows as Out of Sync

A permission problem or an ignore pattern conflict. The Out of Sync items list names the exact files.

FAQ

Frequently asked

Does it need a cloud?

No. Devices connect directly; the relay is only used when a direct connection is impossible.

Can it sync over the internet?

Yes, with the same device IDs and either port forwarding or the relay.

How to undo this

Remove the folder from Syncthing on both sides, then uninstall the app. The files stay where they are; only .stversions can be deleted.

Changelog · 1 entry
  1. 2026-10-30
    First version
Interactive version: checklist, feedback, related guides →

Free · no account needed · tracks your progress