I forgot to correct the subject. I updated to V. 1903.
Thanks for the suggestions. I found it hiding in All Settings-->System-->Sound-->Input (or right click on the speaker icon-->Open sound Settings), where I was able to choose my input device and rename it (to Elecraft K3S RX) and pick the icon for a circuit board. Now it appears in the MMTTY configuration and DXLab's WinWarbler.
The K3S line out is missing.
From: Ed W0YK
Sent: Thursday, June 13, 4:42 PM
Subject: Re: [Elecraft] K3S soundcard after Windows 1809 update
To: Jim N7US, Elecraft Reflector
It just so happens I was at Elecraft a couple hours ago testing a K3/KIO3B with a Win10 1903 notebook and a Win7 notebook. Both saw Line In and Line Out on the Codec.
Did Windows possibly disable the Line Out? Or, is it not even listed?
BTW, is the missing device the K3 LINE OUT (PC Line In) signal, or the PC Line Out (K3 LINE IN) signal?