We pushed a critical security update which has caused driver installation issues for some users. In the meantime here are two community-reported workarounds:
Fix 1: Delete VortxEngine and WhirlwindFX folders from C:\Users\USERNAME\AppData\Local\ then reinstall from signalrgb.com. Keeps your login and profiles.
Fix 2: Go to %appdata%/local/WhirlwindFX/SignalRGB/service, delete SignalRGBService.exe then run the installer.