Brand new windows 10 install on the new x299 dark motherboard, microphone was working last night, then windows updates ran and speakers still worked but mic would not via front panel or directly on back of motherboard. 
 
The specific issue was Windows 10 1803 update installed and broke the microphone. Weird part was I could open the recording devices and enable the "listen" option and I could hear myself so I knew the mic was receiving correctly but discord, skype, etc nothing would pick up me talking or show me mic levels. 
 
Solution was to click on the bottom right notifications icon near the time and date, then all settings, update and security, recovery, then roll back to a previous version of windows a restart will be required. This rolled me back to 1709.
 
After that it will be important to disable windows updates to ensure this does not happen again. Easiest way is to set your network connections (Ethernet or Wireless) to a metered connection (Windows updates dont run on metered connections). Otherwise you can disable the following services BITS, Cryptographic, and windows update.
 
Hopefully Creative will work with EVGA on getting a newer driver package that is compatible with 1803.
 
Hit me up if you have questions.
 
 

I have no issues with my microphone on the latest Win 10 build though :/ In the security tab of Win 10 settings you can disable webcam microphone etc. and this time it really blocks the usage in other apps. Maybe you had that set, or maybe something went wrong during the upgrade. I did a clean install of Win 10