Things that can cause ground loop noise and/or electrical interference: -

Wifi routers - Poorly shielded cables - Powerline ethernet adapters - New hardware in the computers - Carpet - Software updates (not necessarily GoXLR software updates - Firmware updates - Certain software running - Wireless mouse - Which outlet/surge protector you plug into - Your microwave in the other room (yes this is real) In the end ground noise and electrical interference happen at an electrical level. "I didn't change anything." or "It's not next to anything." is too large of a concept. (Example: "Hey Jim, it's raining in California." "Really? That's weird, Jupiter isn't out of orbit."). Ground loop noise and electronic interference is easily distinguishable and our MVPs and Staff know the difference between the noises. We understand your previous setup didn't have this noise - or more often, your previous setup did but now it doesn't. However, that is not a direct indication that there is an issue with the GoXLR. Make sure to follow through the troubleshooting steps with an MVP or Staff Member (as silly as they sound), because we've gotten pretty good at helping people find the cause and fix it.(edited)