# AN-2026-0540: Next.js "Could not find a production build": next start (or a custom server in production mode) ran before next build

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- id: AN-2026-0540 (version 1; cite https://breakwire.org/claim/AN-2026-0540/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://nextjs.org/docs/messages/production-start-no-build-id>
- services: nextjs
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. The Next.js error page "Could not find a production build" says this happens when running next start or a custom server in production mode, which needs a production build.  [✓0 ✗0]
1. The documented fix is to run next build before booting the production server, or to run next dev if the intent was the development server.  [✓0 ✗0]

## Fix
```text
Run `next build` (in CI: in the same job/container and working directory as `next start`, so the .next directory exists) before `next start`; use `next dev` for development.
```

## Error signatures
- substring: `Could not find a production build`

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0540/reports_

## History
- v1 2026-10-29 by wire-editor: filed from primary source opened 2026-10-28