After I upgraded to 24H2 on one of my desktop computers I had the same issue with the realtek driver, and the sound on my external speakers was erratic. I tried everything I could think of and was unable to fix the error. I ended up purchasing this inexpensive external sound "card" and it works perfectly (though device manager still shows the same realtek driver error). If your sound is effected, you might want to try this: Amazon.com
My Computer
At a glance
W11
OS
W11
Computer type
PC/Desktop
Manufacturer/Model
2 HP Desktops, 1 Dell Desktop, 2 Dell XPS Laptops, 1 HP Laptop
Forgot to report what the problem is. Hope this helps someone else. The input device needs to be on Microsoft Array. Not sure why Stereo mix does not work. Wish it did to save all that headache and frustration.
The Stereo Mix is disabled by default and you have to enable it if you want to use it. Some sound cards display no output if you have not connected speakers or earphones. Similarly they display no input of you have not connected a microphone. This is supposed to not confuse novices with inputs or outputs that don't work, but I find it more confusing.
Samsung SSD 850 EVO 250GB SATA Device (250 GB, SATA-III)
Internet Speed
802.11g wireless 54 Mbps
Browser
MICROSOFT EDGE
Antivirus
WINDOWS DEFENDER
Other Info
Legacy MBR installation, no TPM, no Secure Boot, no WDDM 2.0 graphics drivers, no SSE4.2, cannot get more unsupported ;) This is only my test laptop. I had installed Windows 11 here before upgrading my main PC. For my main PC I use everyday see my 2nd system specs.