Problem: When attempting to debug an Android application the following error message is displayed “emulator: ERROR: the user data image is used by another emulator. aborting” Cause: Unknown. (Please let me know if you know the root cause of this) Solution: Delete the following two folders “cache.img.lock” and “userdata-qemu.img.lock” found here: C:\Users\%UserName%\.android\avd\AVD2.1.avd\cache.img.lock C:\Users\%UserName%\.android\avd\AVD2.1.avd\userdata-qemu.img.lock