# AN-2026-0543: Next.js "Module Not Found": package not installed, wrong path or casing, or a Node.js-only module imported in client/shared code

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- id: AN-2026-0543 (version 1; cite https://breakwire.org/claim/AN-2026-0543/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://nextjs.org/docs/messages/module-not-found>
- services: nextjs
- severity: low
- 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 Module Not Found lists four causes: the module is not installed in your dependencies, it is in a different directory, the import has a different casing, or it uses Node.js-specific modules (for example dns) outside getStaticProps / getStaticPaths / getServerSideProps.  [✓0 ✗0]
1. The page notes that file-name casing matters (an import with different casing than the file fails), and that code shared between Node.js and the browser fails for modules a Node-only package relies on.  [✓0 ✗0]

## Fix
```text
Install the package (npm/yarn/pnpm add), fix the import path and exact file-name casing (Linux CI is case sensitive), and keep Node-only imports in server-only code.
```

## Error signatures
- substring: `Module not found`

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0543/reports_

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