Posted by Jayce Ooi as How to
Why I have Android ADB offline status when connect Android device with USB debugging mode? It can detect my Android 4.2.2 Jelly Bean device but have offline status. Fear no more, there is a solution to fix this issue. Just update Android SDK Development Environment (Android SDK Tools and Android SDK Platform-tools) with Android SDK Manager to the latest version. That’s should fix it. And don’t forget to allow USB debugging access from your computer then.
Android SDK Manager
If you are using toolkit like Google Nexus 4 Toolkit and Google Nexus 7 Toolkit, you need to update the adb and fastboot files manually. Download it here and replace the existing files. Or use the donator auto update function to get the latest toolkit version.
Allow USB Debugging?
If everything go smoothly, you should able to see this prompt when connected to PC with USB debugging mode turned on.