1. JavaScript Bundle is Corrupt or Missing
Fix: Clear cache and rebuild Run the following commands to clear your cache and rebuild the JS bundle:
Then, try rebuilding your production app.
2. Hermes JavaScript Engine Issues
Fix: Disable Hermes in expo-config.js If you recently enabled Hermes, try disabling it in app.json:
{ "expo": { "jsEngine": "jsc" } } Then, clean and rebuild:
expo prebuild npx expo run:ios
Alternatively, if Hermes is required, ensure it is properly installed:
expo install hermes-engine Then rebuild the project.
3. App Entry File is Incorrect
Fix: Ensure main.jsbundle is included
Check that index.js or App.js is correctly defined in your package.json:
"main": "node_modules/expo/AppEntry.js"
Run this command to verify your bundle is being created correctly: npx react-native bundle --platform ios --dev false --entry-file index.js --bundle-output ios/main.jsbundle If this command fails, you might have a syntax error in your code.
Fix: Rebuild the native modules If you recently added or removed a package, try reinstalling dependencies:
rm -rf node_modules package-lock.json npm install npx pod-install expo prebuild npx expo run:ios
Fix: Run a production build with logging Try running your app in release mode with logging enabled:
expo run:ios --configuration Release Check for logs in Xcode → Devices & Simulators.
Final Steps If none of the above fixes work:
Run expo doctor to check for configuration issues. Try upgrading Expo & React Native:
expo upgrade Debug in Xcode by opening ios/{YourApp}.xcworkspace and running the app.