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Troubleshooting

npm start doesn’t detect changes​

When you save a file while npm start is running, the browser should refresh with the updated code.

If this doesn’t happen, try one of the following workarounds:

  • Check that your file is imported by your entrypoint. TypeScript will show errors on any of your source files, but webpack only reloads your files if they are directly or indirectly imported by one of your entrypoints.
  • If your project is in a Dropbox folder, try moving it out.
  • If the watcher doesn’t see a file called index.js and you’re referencing it by the folder name, you need to restart the watcher due to a webpack bug.
  • Some editors like Vim and IntelliJ have a “safe write” feature that currently breaks the watcher. You will need to disable it. Follow the instructions in “Adjusting Your Text Editor”.
  • If your project path contains parentheses, try moving the project to a path without them. This is caused by a webpack watcher bug.
  • On Linux and macOS, you might need to tweak system settings to allow more watchers.
  • If the project runs inside a virtual machine such as (a Vagrant provisioned) VirtualBox, create an .env file in your project directory if it doesn’t exist, and add CHOKIDAR_USEPOLLING=true to it. This ensures that the next time you run npm start, the watcher uses the polling mode, as necessary inside a VM.

If none of these solutions help please leave a comment in this thread.

npm start fail due to watch error​

If you are using a Linux operating system and see an error similar to: ENOSPC: System limit for number of file watchers reached, you can fix the issue by increasing the fs.inotify.max_user_watches setting of your operating system.

If you are running Debian, RedHat, or another similar Linux distribution, run the following in a terminal:

echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p

If you are running ArchLinux, run the following command instead:

echo fs.inotify.max_user_watches=524288 | sudo tee /etc/sysctl.d/40-max-user-watches.conf && sudo sysctl --system

Then paste it in your terminal and press on enter to run it. You could find more information here.

npm test hangs or crashes on macOS Sierra​

If you run npm test and the console gets stuck after printing react-scripts test to the console there might be a problem with your Watchman installation as described in facebook/create-react-app#713.

We recommend deleting node_modules in your project and running npm install (or yarn if you use it) first. If it doesn't help, you can try one of the numerous workarounds mentioned in these issues: