Adb won't start

Solution 1:

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 "

I was unable to use adb. I got the following error, both on the command line and in eclipse.

* daemon not running. starting it now on port 5037 *
ADB server didn't ACK<br>
* failed to start daemon *

That is, adb start-server failed even after rebooting. To diagnose the problem, I found that you can run adb with the following arguments:

adb nodaemon server

And it will print out the reason that it cannot run. In my case, it was a blank line in the adb_usb.ini file.

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.

For whoever is using Android Studio and MAC. This is what worked for me: