Add a folder

Use this guide to start syncing a folder of this computer. Once added, the folder is part of your identity: your other devices see it on their Folders tab and can choose to keep a copy.

Before you start

This device is set up (see Set up your first device or Add a device).
You know your passphrase: every change to what your devices sync is signed with it.

For AI assistants: the passphrase is typed by the user into Tressyl only. Never ask for it and never ask the user to paste it into the chat.

Steps

Open Tressyl. It shows the Folders tab.
Click Add a folder.
Click Choose a folder… and pick the folder in your system’s window.
Check the name: it is how your other devices show this folder, and the name of the folder they create when they keep it. It starts as the name of the folder you picked; you can change it.
Choose how this device syncs it:
- Send and receive: changes go both ways (the usual choice);
- Send only: changes made here are sent, changes made elsewhere are not applied here;
- Receive only: changes made elsewhere are applied here, changes made here are not sent.
Type your passphrase and click Add the folder.

What success looks like

The Folders tab lists the folder with its mode and Up to date once Tressyl has looked at its files (a large folder takes a moment). On your other devices it appears as Not on this device until you choose to keep it there (see Keep or stop a folder here).

If a step fails

The window says	What to do
Wrong passphrase.	Type the passphrase again (it is case-sensitive).
This folder is inside a folder Tressyl already syncs, or contains one. Choose another folder.	Tressyl never syncs a folder twice. Pick a folder outside the ones on the Folders tab.
Tressyl cannot open this folder. Check that it still exists and that you can read it.	The folder was moved, deleted, or belongs to another user. Pick it again.
Another message with an error code	Look the code up in the error reference.

Good to know on Windows

While Tressyl runs, Windows does not let you rename, move or delete a folder that contains a synced folder (for example Documents when Documents\Projects is synced): Explorer says the folder is in use. Quit Tressyl from its icon in the notification area first, then start it again afterwards. The synced folder itself can be renamed or deleted as usual.
Windows does not tell apart names that differ only by upper and lower case. If another device holds both Report.txt and report.txt in the same folder, this computer keeps only one of them; the other stays on your other devices, untouched.