Resolving the “Error: EMFILE: Too Many Open Files” in React Native CLI

17 December 2024 Stephan Petzl Leave a comment Tech-Help

When working with React Native projects, you may encounter the error: EMFILE: too many open files. This issue typically arises during the build or start processes, often related to the file watching services used by React Native. Below, we outline effective solutions to address this common problem, drawing from various practical experiences.

Common Solutions

• Close Unnecessary Files: Begin by closing any unnecessary files and applications to free up system resources. This simple action can often alleviate the problem if it’s caused by resource constraints.
• Clean and Rebuild: If you’re developing on Android, navigate to your Android directory and execute ./gradlew clean before running react-native run-android. This process can clear temporary files that might be contributing to the issue.
• Install Watchman: The error often indicates issues with the file watching service. Installing Watchman, a tool for watching changes in the filesystem, can help. Use the following commands:

  $ brew update
  $ brew install watchman

• Node Modules Reinstallation: Sometimes, the error can be linked to node version upgrades. Deleting the node_modules folder and running npm install has proven effective in resolving the issue.

Advanced Troubleshooting

• System File Descriptor Limits: On macOS, adjusting file descriptor limits can resolve persistent issues. Use the following commands:

  $ sudo sysctl -w kern.maxfiles=10485760
  $ sudo sysctl -w kern.maxfilesperproc=1048576

• Use Rosetta for M1 Macs: For users on M1 Macs, running the Metro server in a Rosetta terminal might be necessary. Ensure Watchman is installed using an x86_64 instance of Homebrew, and add it to your PATH.

Conclusion

By following these steps, you should be able to effectively address the “EMFILE: too many open files” error in your React Native development environment. For developers seeking a streamlined approach to app testing, consider exploring Repeato, a no-code test automation tool. Repeato leverages computer vision and AI, offering a swift and user-friendly way to create, run, and maintain automated tests for React Native apps.

For more detailed guidance on testing and automation, visit our documentation page.

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