I've been using an 1810c on Win11 for over two years and a couple of UC updates with no problems, so I'm can only WAG (wild a$$ guess) a couple of things to check.

When you installed UC, did you deselect all of the drivers except for the Studio USB one? They are all checked by default, and it's a pain to manually deselect each one, but I've always done that. My laptop has a 4K display, but the install window doesn't scale, so it's really hard to see the check marks.

Have you installed any other audio apps, like VB Audio's Voicemeeter?

I assume that you're using the ASIO driver for the 1810c. How do you have Windows sounds configured? Since the ASIO driver isn't multiclient, I sometimes use the internal Realtek driver for the laptops speakers and ASIO for the studio monitors connected to the 1810c. Also, I've had issues in the past with Windows sample and bit rates being different than the 1810c's sample and bit rates.

Also, at least one of my bass amp sim VSTs generates low level audio when it has no input, a real pain. I haven't figured that one out yet.

Thanks for the reply.

When installed the drivers I installed the Studio driver and the AudioBox driver since I have both interfaces. Yes, using the ASIO Studio driver

Other Audio Apps? I don't understand. I have Studio One Artist and Pro Tools installed. I haven't installed any other audio drivers devices if that's what you mean

My Windows 11 came with NVidia HD Audio as the default audio output device, but I disabled it.

I either use the Presonus for sound when tracking, or if I am just messing around, I use a bluetooth speaker for sound.

Where would I find Windows sample and bit rates?