Adb won't start

This problem has annoyed me for a long time. In addition to the above answer, use these tips:

• Create a bat file with the following and run it. This bat file will solve most of your adb problems.

tskill adb

cd \tools\

adb kill-server

adb start-server

ddms

• Use the command netstat to monitor the state of connections (adb uses 5037)

• If the bat file doesn't work try: disconnect-reboot phone-connect. (hint: use `adb reboot' if adb is responding at all, if not do it the old fashioned way)

• Sometimes Windows can be funny. Reboot the machine.

• Turn on USB Debugging Mode

  • Download the Android SDK and unzip
  • Uninstall all "Android *" from Device Manager
  • Do an "Add Hardware" from Control Panel, choosing "Install the hardware... (Advanced)"
  • Select "Android USB Devices" and click "Next"
  • Click "Have Disk" and enter the path where the SDK was unzipped

• Still not working ? Factory reset the phone.

• MTP detection delays ADB. Sometimes you if need boot time logs you may have to disable the MTP driver in Device Manager (Windows)

This is a brilliant patch for adb when you get the error :

Adb connection Error:An existing connection was forcibly closed by the remote "

You may have a stuck copy of the adb daemon in memory. Try removing it with Task Manager, or reboot, and see if that helps.

When it additionally says that adb server is out of date. killing... it kills it for you. The problem is it restarts as soon as was killed.

So you should consider finding the adb.exe wherever it could be. The simplest way to do that is opening a Task Manager, finding an adb.exe process -> RMB -> Open file location -> delete it from there. Unless it's not needed, in this case you should update it. In my case it was in C:\Windows\ and came with their Visual Studio.

Usually the answers given here worked for me, but today they didn't. My problem was fixed by updating the emulator and SDK to the latest versions from the SDK manager.