Moonpool error messages explained: already running, requires a command and more

Paste the message you see into the page search, or scan the tables. Messages are quoted as Moonpool shows them. Text in <angle brackets> is replaced by a value (an app id, a path or an error from the system). Symptoms that are not an error message are on Troubleshooting and FAQ.

Starting and stopping an app

Message	Meaning and fix
`already running`	Moonpool already holds a terminal for this app. Stop it first, or use Restart.
`stopped during launch`	Stop was pressed while the launch was still starting. Launch again.
`app has no launch command`	The entry has no `command`. Add one in the app editor or in `apps.json`. Only a `static` entry with a `url` can go without.
`unknown app: <id>`	No app with that `id` is loaded. Check the id, then Reload if you edited `apps.json` by hand.
`unknown app id: <id>`	The same problem, reported to a script or agent. List the apps with `moonpool_list_apps`.
`did not reach running in time`	From a script or agent: the app did not read as Running within 25 seconds. Check `port` or `processName`, and read the output. See The status dot is wrong.
`still running after stop`	After 15 seconds the app still reads as Running. Set `killMode`. See Stop and restart.
`refusing to open non-web url: <url>`	The `url` is not `http://`, `https://`, `mailto:` or `file://`. Fix the `url`.
`[process exited]`	Not an error: the app’s command ended. Shown in the terminal tab.

apps.json validation

Moonpool rejects an apps.json that breaks a rule and keeps the last list that loaded. <n> is the entry’s position in the file, counting from 1.

Message	Fix
`apps.json entry <n> has invalid id "<id>"; use letters, digits, '.', '_', and '-' without a leading '-'`	Rename the `id`.
`duplicate app id "<id>"`	Two entries share an `id`. Make each unique.
`apps.json entry <n> (<id>) has an empty name`	Fill in `name`.
`apps.json entry <n> (<id>) has an empty group`	Fill in `group`.
`apps.json entry <n> (<id>) has unknown type "<type>"`	`type` must be `web`, `desktop`, `static` or `cli`.
`apps.json entry <n> (<id>) has invalid port 0`	`port` must be 1 to 65535.
`apps.json entry <n> (<id>) requires a url`	A `static` entry needs a `url`.
`apps.json entry <n> (<id>) requires a command`	Every other type needs a `command`.

In the app editor, saving without a name shows name is required.. The banner text, “apps.json has an error, showing the last list that loaded.” or “apps.json has an error, so no apps are loaded.”, and how to recover are under apps.json has an error. If the banner says saving is paused, the message ends Repair apps.json and reload it before saving from Moonpool. The full rule list is in Validation.

Settings, updates and the installer

Message	Meaning and fix
`... Repair settings.json and restart Moonpool before changing settings`	`settings.json` is malformed. Fix or delete it and restart. See settings.json.
`Update failed: <error>`	The download or install of an update failed. See When an update fails.
`Update check failed: <error>`	The update check in About failed. The text after the colon says why. Try again later.
`Install failed: <error>`	The installer stopped at the step named after the colon, for example `copy exe: ...`. Quit any Moonpool running from `%USERPROFILE%\.moonpool` and retry.
`target folder does not exist`	The folder picked for a portable copy is gone. Pick an existing one.

MCP and scripts

Message	Meaning and fix
`Moonpool is not running - call moonpool_bootup_launcher first`	Start Moonpool, or let the agent call that tool. For a portable copy the message names the copy.
`frontend not loaded`	The hub window has not finished loading. Wait and retry.
`invalid app_id: use only letters, digits, '.', '_', '-' (no leading '-')`	The agent passed an id the MCP server will not accept. Use the id from `moonpool_list_apps`.
`stale token: apps.json changed since it was read ...`	Read `apps.json` again, reapply the edit, then write.
`rejected invalid manifest: ...`	The new `apps.json` failed validation (see above). The file was not changed.
`no console output recorded for '<id>' (not launched this session)`	`moonpool_app_output` was asked for an app that has not run since Moonpool started.

Errors from other programs

Moonpool is free software from FasterDB