"Module not found: Can't resolve" — builds locally, fails on deploy

What it means

The build can't find a file or package your code imports.

Why AI tools cause it

Three usual suspects:

• Letter case. Your import says ./components/Button but the file is button.tsx. Mac and Windows ignore case; the Linux servers your host builds on don't.
• A package that isn't installed. The AI wrote an import but never added the package to package.json.
• A file that was never committed, so it exists on your machine but not in your repo.

The fix

1. Read the error: it names the exact import that failed.
2. Check the file name's capital letters match the import exactly. To rename only the case in git, use git mv button.tsx Button.tsx.
3. If it's a package, install it (npm install <name>) and commit package.json and the lock file.
4. Run git status to check nothing important is uncommitted.

Paste this into your AI

My deploy fails with "Module not found: Can't resolve ". Check every import in this project matches the real file name, including capital letters, and list any imported packages missing from package.json.

Still broken?

Clear your host's build cache and redeploy.