`yarn start` fails with error message

[mocheng]

Description

yarn startfails with below message

yarn start v0.15.1
$ "react-scripts start"
sh: react-scripts start: command not found
error Command failed with exit code 127.
info Visit http://yarnpkg.com/en/docs/cli/start for documentation about this command.

Expected behavior

According to the prompt after creating a project, yarn star should work.

We suggest that you begin by typing:
cd xyz
yarn start
Happy hacking!

Actual behavior

Tell us what actually happens.

Environment

node -v
v7.2.0

npm -v
3.10.9

create-react-app --version                                                                                                                 
create-react-app version: 1.0.0

Operating system: MacOSX 10.12.1

Reproducible Demo

1. Globally install create-react-app and create one project called xyz.
2. Follow the prompt instructions;
3. yarn start fails, but npm start works.

[gaearon]

I can't reproduce with Yarn 0.17.6.
Can you please run yarn self-update and try again?

[dchambers]

Hey @gaearon, I just ran into the same problem. For me, yarn self-update didn' work (as explained here), but I was able to get past that by using npm -g install yarn instead, and it worked as expected after that.

[mocheng]

After upgrading yarn to 0.17.10, it turns to be working.

[zverbatim]

worked for me after running just the command yarn in project folder

[zawmoelwin]

It works. Thanks @zverbatim .
For me, accidental npm install --save the package induced the error.

the solution is ..
reset the git
yarn
then yarn add packageName solved the error.

[n1c01a5]

yarn upgrade

[peggyc3]

I had a similar problem, caused by installing a package using npm instead of yarn, which is what I was using for this project. I got the react script not found error message and the server would not start. To fix it, I ran yarn, then ran yarn start and the server restarted. SUCCESS :)

[y0n1]

Well, I know I'm joining the party a bit late... but this was my setup:

• macOS (High Sierra)
• I'm using NVM
• I've installed Yarn using Brew

So, when I stumbled upon this issue the only thing which helped me was:

1. brew uninstall yarn
2. rm $(which yarn)
3. rm -rf ~/.config/yarn

Then,

• brew install yarn

Hope this helps somebody too

[dapperAuteur]

having the same issue, yarn self-update didn't work for me. I ran yarn -v and it printed my version then updated. I was on 0.24.6. It works now.

[Arpanbhalla]

yarn upgrade

I experiences the yarn start error on 4 different laptops running Ubuntu and resolved it using these steps.
The underlying issue was that the yarn path was set incorrectly.
If you have this error then you will see a yarn-error.log file in you project directory rather then a normal yarn.log file.
But if you reinstall Yarn on Ubuntu, it will also CORRECT Your React * path to yarn and this error.

Here the steps:

1- curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
2- echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
3- sudo apt-get update && sudo apt-get install yarn
4- sudo apt-get upgrade
- Then Reboot/Restart your System

-- After you did these STEPS, Go To Your Project and BUILD & START Your Yarn:
1. yarn bulid
2. yarn start

Now, after you created a new 'React' Project, you should see the (( yarn.lock )) file in your project folder!

		Then start with:
1.		yarn build
2.		yarn start

I'm facing the same issue "yarn run v1.12.3" but i still get this error
error Command "start" not found.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.