React app created using create-react-app failing to start, returns error

Question

I used create-react app to create a new react application, when I try to start it using the command npm start, it returns the following error:

> warbler-client@0.1.0 start 
/mnt/c/Users/Debchakra/Desktop/warbler/warbler-client
> react-scripts start


There might be a problem with the project dependency tree.
It is likely not a bug in Create React App, but something you need to fix 
locally.

The react-scripts package provided by Create React App requires a 
dependency:

  "webpack": "4.28.3"

Don't try to install it manually: your package manager does it 
automatically.
However, a different version of webpack was detected higher up in the 
tree:

  /mnt/c/Users/Debchakra/node_modules/webpack (version: 4.29.5)

Manually installing incompatible versions is known to cause hard-to-debug 
issues.

If you would prefer to ignore this check, add SKIP_PREFLIGHT_CHECK=true to 
an .env file in your project.
That will permanently disable this message but you might encounter other 
issues.

To fix the dependency tree, try following the steps below in the exact 
order:

  1. Delete package-lock.json (not package.json!) and/or yarn.lock in your 
project folder.
  2. Delete node_modules in your project folder.
  3. Remove "webpack" from dependencies and/or devDependencies in the 
package.json file in your project folder.
  4. Run npm install or yarn, depending on the package manager you use.

In most cases, this should be enough to fix the problem.
If this has not helped, there are a few other things you can try:

  5. If you used npm, install yarn (http://yarnpkg.com/) and repeat the 
above steps with it instead.
     This may help because npm has known issues with package hoisting 
which may get resolved in future versions.

  6. Check if /mnt/c/Users/Debchakra/node_modules/webpack is outside your 
project directory.
     For example, you might have accidentally installed something in your 
home folder.

  7. Try running npm ls webpack in your project folder.
     This will tell you which other package (apart from the expected 
react-scripts) installed webpack.

If nothing else helps, add SKIP_PREFLIGHT_CHECK=true to an .env file in 
your project.
That would permanently disable this preflight check in case you want to 
proceed anyway.

P.S. We know this message is long but please read the steps above :-) We 
hope you find them helpful!

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! warbler-client@0.1.0 start: `react-scripts start`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the warbler-client@0.1.0 start script.
npm ERR! This is probably not a problem with npm. There is likely 
additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/webdeb/.npm/_logs/2019-03-26T06_44_19_294Z-debug.log

I tried all the steps mentioned above, like install yarn and all that, but it always shows the same error.

Previously, I have used create-react-app inside if cloud9, it worked fine then, but now I am doing it on my local system. And I actually using WSL. (if that helps)

Answer 1

You already have a version of webpack installed globally on your system ( /mnt/c/Users/Debchakra/node_modules/webpack (version: 4.29.5) ) which does not match the version required by create-react-app.

Uninstalling the global version via npm uninstall -g webpack should fix it.