Resolving Unauthorized Device Error in Android ADB

Resolving Unauthorized Device Error in Android ADB

30 November 2024 Stephan Petzl Leave a comment Tech-Help

Encountering an “unauthorized” device error while using ADB (Android Debug Bridge) can be frustrating, especially when you’re trying to connect a device for debugging or development purposes. This guide will walk you through the steps to resolve this issue effectively.

Understanding the Issue

The “unauthorized” error typically occurs when the Android device does not recognize the ADB host, often due to security features introduced in Android 4.2.2 and later versions. These security measures require user authorization to allow USB debugging.

Step-by-Step Solutions

Here are several solutions you can try to resolve the unauthorized device error:

1. Verify USB Debugging and Connection

  • Ensure USB Debugging is enabled on your device. You can do this by navigating to Settings > Developer Options > USB Debugging.
  • Try unplugging and replugging the USB cable. This simple action can sometimes prompt the authorization dialog on your device.
  • If prompted, authorize the computer by checking the “Always allow from this computer” option.

2. Restart ADB Server

Sometimes the ADB server may need a restart to recognize the device properly:

adb kill-server
adb start-server

3. Synchronize ADB Keys

If the above steps don’t work, you may need to manually synchronize the ADB keys:

  • Get the public key from the client phone (ADB host) using the command:
cat /data/.android/adbkey.pub
  • Copy the public key to the target phone’s /data/misc/adb/adb_keys location. You may need to stop the ADB daemon first:
  • stop adbd
  • Verify both cat outputs match, then restart the ADB daemon:
  • start adbd

    4. Update ADB Version

    Ensure your ADB client version is up-to-date, as older versions may not support newer security features. The feature to authorize devices was supported from ADB version 1.0.31.

    Leveraging Automation with Repeato

    For developers looking to streamline their testing process, Repeato offers a compelling solution. As a no-code test automation tool for iOS and Android, it allows you to create, run, and maintain automated tests efficiently. Particularly useful is its ability to execute ADB commands via “script steps,” enabling precise timing and sequencing of commands. This feature can be invaluable when troubleshooting ADB connectivity issues, as it allows for automated testing scenarios that include ADB command execution.

    For further reading on related topics, consider visiting our blog or explore detailed guides in our documentation.

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