# Fix Module Not Found Error

> Diagnose and fix `ModuleNotFoundError` in Nuitka standalone binaries caused by missing implicit imports. Use when a compiled program fails at runtime because an imported module was not included.

- Skill: `nuitka/fix-module-not-found-error` (Agent Skill)
- Install (CLI): `npx skillmds@latest add nuitka/fix-module-not-found-error`
- Raw SKILL.md: https://api.skillmd.com/api/skills/nuitka/fix-module-not-found-error/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: nuitka (https://skillmd.com/u/nuitka)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/nuitka/fix-module-not-found-error

---


# How to fix ModuleNotFoundError in Nuitka

This workflow guides you through resolving `ModuleNotFoundError` when running a Nuitka-compiled
binary, specifically caused by missing implicit dependencies (e.g., hidden imports in Cython
modules).

## 1. Reproduction and Analysis

1. **Isolate the error**: Create a minimal reproduction script (MRE) that triggers the
   `ModuleNotFoundError`. Follow `.agents/skills/create-mre/SKILL.md` for the reduction workflow.
2. **Verify the crash**: Run the MRE with Nuitka in standalone mode to confirm the error persists.
3. **Analyze the traceback**:
   - Identify the missing module name (e.g., `pandas._libs._cyutility`).
   - Identify the importer module (e.g., `pandas._libs.tslibs.ccalendar`).
   - *Note*: If the importer is a compiled extension (e.g., `.pyx`, `.so`, `.pyd`), Nuitka cannot
     automatically detect imports inside it.

## 2. Locate Configuration

1. **Find the configuration file**: Most package-specific configurations are in
   `nuitka/plugins/standard/standard.nuitka-package.config.yml`.
2. **Search for the package**: Look for the top-level package (e.g., `pandas`) or the specific
   submodule in the YAML file.

## 3. Implement the Fix

1. **Add Implicit Import**:

   - If the importer module already has an entry, add the missing module to its `implicit-imports`
     -> `depends` list.
   - If the importer module is missing, create a new entry for it.

   ```yaml
   - module-name: 'importer.module.name'
     implicit-imports:
       depends:
         - 'missing.module.name'
   ```

2. **Verify the fix**: Re-run the MRE compilation.

   - Ensure the `Nuitka-Plugins:implicit-imports` log shows the dependency being added (if verbose
     logging is enabled).
   - Run the compiled binary and confirm it executes without the `ModuleNotFoundError`.