Short answer: start the daemon. On Linux: `sudo systemctl enable --now tailscaled`. Then run `sudo tailscale up` again. ``` failed to connect to local tailscaled; it doesn't appear to be running (sudo systemctl start tailscaled ?) ``` 1. Run `sudo systemctl enable --now tailscaled`. This starts the daemon now and keeps it enabled across reboots. Expected: no output means success. 2. Confirm with `systemctl is-active tailscaled`. Expected: `active`. 3. Retry `sudo tailscale status`. Expected: your node's info, not the connect error. 4. If the service will not stay up, read `journalctl -u tailscaled -n 50`. Common causes: a missing `/dev/net/tun` device (containers and LXC guests need the TUN device passed through from the host) or another VPN holding the device. 5. Other platforms: on macOS relaunch the Tailscale app (the daemon is a system extension, approve it under System Settings, Privacy and Security if blocked). On Windows start the Tailscale service in services.msc. Snap installs: `sudo snap restart tailscale`. Root cause: client/daemon split. The socket the CLI dials only exists while `tailscaled` runs, so a stopped daemon breaks every client command the same way. When to use: this exact message on any OS. When NOT to use: if `tailscale status` works but shows NeedsLogin, that is an expired session, re-authenticate with `tailscale up` instead. Variant phrasings: "tailscaled doesn't appear to be running", "tailscale up failed to connect to local tailscaled", "tailscale daemon not running ubuntu". Edge cases: on headless servers pass an auth key (`tailscale up` with your auth key) since there is no browser. Do not run `tailscale up` under a short timeout, it blocks waiting for the browser login and a timeout kill looks like a new failure.

Context: The `tailscale` command you type is only a client. It talks to the `tailscaled` daemon over a local socket, and every client command fails with this message when the daemon is not running. This is not a network, account, or install problem. It means the background service is down or was never started.