zed-industries/zed · error

ssh process exited before connection established

Error message

ssh process exited before connection established

What it means

On the Windows connect path, wait_connected reads ssh's stdout line by line until the ZED_SSH_CONNECTION_ESTABLISHED magic appears; read_line returning 0 bytes is EOF, meaning the ssh master process exited before it ever printed the marker, so connection establishment cannot complete.

Source

Thrown at crates/remote/src/transport/ssh.rs:279

        Ok(MasterProcess { process })
    }

    pub async fn wait_connected(&mut self) -> Result<()> {
        use smol::io::AsyncBufReadExt;

        let Some(stdout) = self.process.stdout.take() else {
            anyhow::bail!("ssh process stdout capture failed");
        };

        let mut reader = smol::io::BufReader::new(stdout);

        let mut line = String::new();

        loop {
            let n = reader.read_line(&mut line).await?;
            if n == 0 {
                anyhow::bail!("ssh process exited before connection established");
            }

            if line.contains(Self::CONNECTION_ESTABLISHED_MAGIC) {
                return Ok(());
            }
        }
    }
}

impl AsRef<Child> for MasterProcess {
    fn as_ref(&self) -> &Child {
        &self.process
    }
}

impl AsMut<Child> for MasterProcess {
    fn as_mut(&mut self) -> &mut Child {
        &mut self.process

View on GitHub (pinned to f4178619ac)

Solutions

1. Run the equivalent command manually to see why ssh exits: `ssh -vvv <user>@<host>` in a terminal
2. Fix user/port/credentials in Zed's remote connection options
3. Install or repair the OpenSSH client (Windows Settings > Apps > Optional Features > OpenSSH Client) and confirm `where ssh` resolves it
4. Pre-accept the host key: `ssh-keyscan <host> >> known_hosts`, or pass StrictHostKeyChecking=accept-new via additional ssh args

Example fix

# before: OpenSSH client missing on Windows, ssh exits instantly
where ssh   # not found

# after (PowerShell, admin)
Add-WindowsCapability -Online -Name OpenSSH.Client~~~~0.0.1.0
# reconnect from Zed

// Preflight from a terminal: a zero exit means ssh gets far enough to establish
// ssh -o BatchMode=yes -o ConnectTimeout=5 -T <user>@<host> true; echo $?

match master.wait_connected().await {
    Err(e) if e.to_string().contains("exited before connection established") => {
        // run `ssh -vvv user@host` manually and surface the real cause (auth/host/network)
        Err(e)
    }
    other => other,
}

When it happens

Trigger: The ssh.exe master process terminates during the handshake: authentication failure, unreachable host, bad port/user, malformed ssh arguments, or ssh.exe missing from PATH so the spawn target fails immediately.

Common situations: Windows machines without the OpenSSH client optional feature installed; wrong username/port in the remote connection options; host key prompts hitting a non-interactive channel; mistyped or stale connection settings.

Related errors

• failed to connect: {}
• connecting to host timed out
• Device lost: {err}
• build ids may only contain lowercase letters, numbers, '.',
• unknown judge preset '{name}' (valid: {valid})

AI-assisted analysis of zed-industries/zed@f4178619ac (2026-08-20). Data as JSON: /api/errors/eaccf3066ab95bc2. Report an issue: GitHub.