React Native Android build succeeds but fails with Error type 3: Activity class does not exist

Frontend Android
1

Issue I Faced

I was trying to run my React Native project with product flavors.
When I executed:

npm run android:dev
  • The build succeeded.
  • The APK was not installing properly on my device.
  • After a partial install, launching the app gave:
Error type 3
Error: Activity class {<applicationId>/<mainActivity>} does not exist.

So the app either didn’t install fully or couldn’t launch.

Root Cause

The issue happened because a previous version of the app was already installed on the device. Android couldn’t overwrite the old APK correctly, which led to installation issues and Error type 3.

How I Solved It

  1. Uninstall the old app completely:
adb uninstall <applicationId>.develop
  1. Clean the build:
./gradlew clean
  1. Reinstall the APK:
npm run android:dev

After this, the app installed correctly and launched successfully.

Tip for Others

  • If you switch flavors (dev, staging, prod), uninstall the previous variant first.
  • You can combine uninstall + clean + run into a single command:
adb uninstall <applicationId> && ./gradlew clean && npm run android:dev
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