Fix Gatsby 'cannot find module gatsby-cli/lib/reporter'

This records a historical dependency incident. Switching from npm to Yarn is not a general fix for missing modules. Use the package manager and lockfile already chosen by the project.

The fix for the Gatsby Cannot find module 'gatsby-cli/lib/reporter' error is to delete node_modules and reinstall your dependencies from scratch. Let me show you what happened to me, and why this works.

I created a site using Gatsby and I ran gatsby develop to start a local server.

But a weird error showed up, coloring with red my terminal:

What does the error mean?

Node.js throws Cannot find module when it can’t resolve a file that some code is trying to load. In this case the missing file is lib/reporter, part of the gatsby-cli package. It’s the module Gatsby uses to print progress and errors to the terminal.

That file lives inside node_modules. If Node can’t find it, node_modules is in a broken state. Maybe an install got interrupted halfway. Maybe a package was updated but only partially written to disk.

A very common cause is mixing package managers. If you run npm install at one point and yarn at another, each tool lays out node_modules in its own way, and you can end up with a folder that’s half one and half the other.

The fix

After a few searches across GitHub and StackOverflow (I found a lot of people with the same problem!) this is what fixed the error.

First, I deleted node_modules:

rm -rf node_modules

then I used yarn instead of npm install:

yarn

This installed all the packages again, from scratch, in a consistent state.

Finally I ran gatsby develop and it worked.

Not sure what the cause problem is/was, but I tried again running npm install instead of yarn and it didn’t work. My project had a yarn.lock file, so my guess is yarn recreated the exact dependency tree the project was built with, while npm resolved a slightly different one.

What if this doesn’t fix it for you?

A few variations of the same cleanup helped other people hitting this error.

Delete the lockfile too, package-lock.json or yarn.lock, before reinstalling. You lose the pinned versions, so dependencies get resolved again, but that can clear a corrupted resolution.

Also check if you have an old global gatsby-cli installed. A version mismatch between a global CLI and the local Gatsby packages in your project can cause similar module errors. Prefer running the local version through your project’s npm scripts.

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