'Module not found' errors are often due to missing packages, incorrect file paths, or incompatible Node versions. Check the package, file path, and Node version.

A 'module not found' error in Node.js typically indicates that a required package or file isn’t accessible. Start by verifying the package is installed correctly with npm list <package-name> and check if it appears. If not, install it via npm install <package-name>. Ensure the file path is correct, especially for custom modules; Node.js follows relative pathing, so check the file location using require('./path-to-file'). For global modules, verify they’re in your environment’s PATH by using npm config get prefix and adding this to your system PATH if necessary. Additionally, check for any discrepancies in Node version requirements by reviewing engines in package.json and ensuring your project uses a compatible Node version. Tools like nvm (Node Version Manager) make switching Node versions seamless. Regular audits of node_modules with npm prune can help identify and remove unused packages, while clearing cache (using npm cache clean --force) prevents conflicts with outdated versions.