Internal Speakers disappeared from Sound Preferences on MacBook Pro
How do I restore my internal speakers on my MacBook Pro (13-inch, 2017, Two Thunderbolt 3 ports)? They have just disappeared and I have no sound at all. Help!
Reboot?
Try resetting NVRAM/PRAM http://support.apple.com/kb/ht1379
Try resetting the SMC https://support.apple.com/en-us/HT201295
further troubleshooting: Get help if the internal speakers on your Mac don't make sound - Apple Support