Android Studio : emulator is already running
Solution 1:
You don't have to completely delete the emulator when this happens. The files to delete should have a ".lock" extension:
You don't need to touch the configuration files.
You can easily find the files location by clicking on the arrow under the Actions tab (in the ADB manager), and selecting "Show on Disk".
Solution 2:
This worked for me:
Go to AVD Manager and click on the down-arrow on the right and click Stop. This stops the emulator and you can re-run it.
Solution 3:
There are so many answer but i just extending to give answer of this question. What happen is when i follow Android Studio instruction and try to delete that folder Or file but i am not able to delete it, So what am i do is that i open the AVD Manager and click on down arrow which is on right side as you can see in below screenshot and click on stop after click on start and its working fine. There is no need to restart or recreate the AVD.
Solution 4:
Go to the down arrow and click on the "Show on Disk" link like attached image. You will get the list of all files, remove the file "hardware-qemu.ini.lock" and start again.
It works for me hope it will work for you too.