since update on Sierra 10.12.4 my macbook air doesn't have no more sounds, no starting-gong etc. In the control panel I cannot choose intern speakers
I have a Macbook Air, 1,7 GHz Intel Core i7 with 8 GB 1600 MHz DDR3
After the update on Sierra 10.12.4 it has no more sounds at all even not the starting gong.
In the control panel there are no intern speakers available to choose. there is just the option "Soundflower", a program which I already tried to uninstall.
In addition I contacted the support. They told me to re-install MacOS Sierra which I did but didn't help.
MacBook Air, macOS Sierra (10.12.4)