Ubuntu - No audio after disconnecting from HDMI

1. Open PulseAudio Volume Control. Install it if you don't have it.
2. Install it if you don't have it., To install it apt-get install pavucontrol
3. When you open it, go to "Configuration" : For one of the "built in audios" one has HDMI (unplugged) in front of "Profile". Choose "Off" for that profile as below image.

./Enjoy Fixing.