Android Launch! The connection to adb is down, and a severe error has occured

If you get this error, when you try to launch your Android app on Emulator device, then simply try the following troubleshooting steps.

1. Close you Eclipse IDE
2. Locate your adb tool (you may simple find the path from the error logs)
3. Now open Command Prompt/Terminal depending on if you are on Mac OS X or Windows.
4. Execute command adb kill-server
5. Now Open Eclipse IDE again and try running you app, there should be no issue.

If you still facing the issue, then it may be that ADB process is was not killed properly.

For Windows,

1. Close Eclipse IDE.
2. Go to task manager (ctrl+alt+del)
3. Look for adb.exe
4. Terminate/End the process.
5. Now Open eclipse and launch AVD.

For Mac OS X,

1. Close Eclipse IDE.
2. Open Activity Monitor from Spotlight
3. Under Cpu tab, look if eclipse/adb process is running
4. Double Click on the Process name and Exit it.
5. Restart Android Eclipse IDE and run AVD again