How to restart ADB manually from Android Studio

Open Command prompt and go to

android sdk>platform-tools>

adb kill-server

press enter

and again

adb start-server

press enter

open command prompt -> cd to your sdk\platform-tools type below command:

adb kill-server && adb start-server

1. Open a Task Manager by pressing CTRL+ALT+DELETE, or right click at the bottom of the start menu and select Start Task Manager. see how to launch the task manager here

2. Click on Processes or depending on OS, Details. Judging by your screenshot it's Processes.

3. Look for adb.exe from that list, click on END PROCESS

4. Click on the restart button in that window above. That should do it.

Basically by suddenly removing your device ADB got confused and won't respond while waiting for a device, and Android Studio doesn't want multiple instances of an ADB server running, so you'll have to kill the previous server manually and restart the whole process.