# Troubleshooting (/docs/users/troubleshooting)



## Start with `cento doctor` [#start-with-cento-doctor]

```bash
cento doctor
```

`doctor` checks everything a working Cento machine needs — disk space, the
background daemon, automatic startup, pairing, and (on Windows) WSL — and
prints a structured report:

* **Exit code 0** — your machine is fully ready. There is no partial success.
* **Nonzero** — one or more gaps, each with what's missing and what to do.

Scripts and coding agents can consume the same report as JSON:

```bash
cento doctor --json
```

## Common fixes [#common-fixes]

| Symptom                                | Fix                                                                    |
| -------------------------------------- | ---------------------------------------------------------------------- |
| Machine shows offline in the dashboard | `cento host install` — it restarts the daemon and re-registers startup |
| Not paired / login expired             | `cento login`, then approve in the browser                             |
| Broken or partial install              | Re-run the install command — it converges rather than duplicates       |

## Re-running install is safe [#re-running-install-is-safe]

`cento host install` is idempotent. When in doubt, run it again: it fixes
what's missing and leaves what works untouched.