Yes, that can be maddening. The very good news in your post is that it worked once. All I can say, without having your equipment, is methodically follow the signal path. Pay particular attention to mixer settings. With two sound cards, you have three: one for each card, and one for Windows.

Did a channel get muted?

Has your equipment or cabling changed?

Did you install new software?

Why two sound cards (not necessarily wrong, but adds to the complexity as you said), and how are they connected?


BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.