# SC999: Unexpected error

> SC999 (unexpected error) means shutdown-check itself hit an error it did not plan for. Read the message, check the config, or report it with the timeline.

Source: https://shutdown.jscrate.dev/docs/codes/sc999
Last updated: 2026-09-23

`SC999` means shutdown-check caught an error that does not belong to a normal
failure stage. The message comes from the original error, so it is the best
place to start.

| | |
| --- | --- |
| Code | `SC999` (FAIL) |
| Stage | Unexpected errors |
| CLI exit code | 1 |
| What it means | The check itself hit an error it did not expect, such as an unsafe request path or an operating-system failure. |
| Message |  |
| First thing to check | Read the message in the result; if it points at shutdown-check rather than your service, open an issue with the timeline. |

## What should I do first?

1. Read the full message and the last timeline event.
2. If you call `runCheck()` directly, validate the object with `parseConfig()`.
3. Try the same config through `checkShutdown()` or the CLI.
4. Confirm the environment is supported and has enough system resources.

A hand-built `CheckConfig` can bypass normal validation and cause errors such
as an unsafe request path. The higher-level APIs catch those values before the
run begins.

## When should I report a bug?

Report the problem when a valid config repeatedly returns `SC999`. Include the
package version, operating system, Node.js version, config with secrets
removed, result message, timeline, and a small reproduction if possible.

## How do I rule out a config problem?

Run the same input through `parseConfig()` or use the CLI. If validation
rejects it, fix that error first. If validation passes and SC999 repeats, keep
the original message unchanged for the issue report.

Never include credentials, private URLs, tokens, or customer data in the
reproduction.

## Related

- [Node API validation](https://shutdown.jscrate.dev/docs/node-api#validate-input-with-parseconfig)
- [Troubleshooting](https://shutdown.jscrate.dev/docs/troubleshooting)
- [About and support](https://shutdown.jscrate.dev/docs/about)