That's pretty much it. Using WSJT-X 2.0.1 on Windows 10. Microphone (CODEC) input signal level is at 61, which worked well before. When I switch the Signalink output to a laptop running Linux Mint (same USB cable), I get many more signals decoded, so the problem appears to be somewhere in the Windows machine. But where? Edited to add: the decoding appears to be independent of signal strength: out of what appears to be a dozen signals on the waterfall, it might decode a +2 and a -19. G.