When I launch the emulator I face many problems (Errors):-
HttpConnectionApp]emulator-5554 disconnected!
Cancelling \'net.paxcel.http.HttpConnectionApp activ
Delete the directories cache.img.lock and userdata-qemu.img.lock (in my case these files are in /mylocalusername/.android/avd/avd7.avd
I had the same issue after my computer locked up and I had to power cycle it.
Wiping the user data didn't fix my problem, I had to delete the following folders manually
C:\Users\%UserName%\.android\avd\AVD2.1.avd\cache.img.lock
C:\Users\%UserName%\.android\avd\AVD2.1.avd\userdata-qemu.img.lock
Here is the answer that helped me: link text
Another solution for me is start the avd manager and start once emulator from there. After that everything turns to normal.
AFAIK, this happens when an emulator is started, but the Android Debug Bridge couldn't establish connection to it.
If you have just started the emulator with your application, watch if you get Waiting for HOME to launch...
or something similar in your Console.
If you don't get that message, but the emulator has been started, chances are, you'll get into the ERROR: the user data image is used by another emulator
situation again.
Delete the existing emulators and then make a new one.
This worked for me, when I had this problem and couldn't find the folders to delete.
This can also happen if you're using a network share as your home folder, because some network file sharing systems may lock the image files.