I am not sure if this is the exact fix for you BUT I have this problem. If I open Cubase Pro with Youtube running a video in the background (in Google Chrome), Cubase will NOT allow the Drivers of my I/O to run. The result is the faders still show movement but no sound.
The fix for me is to close ANY programs playing sound on my PC and restart Cubase. Oh, I also have the Release Driver ticked and this issue still happens. I just figure Cubase needs to monopolise the sound drivers so I let it.
The release AUDIO is not really about running multiple audio using programs…
SEE THIS FROM THE STEINBERG website…
Release ASIO Driver in Background
This can be necessary when the ASIO driver is not “multi-client” capable but you want to use your audio hardware with another application beside Cubase/Nuendo.
When you start an audio export the ASIO driver is used. When the option “Release ASIO Driver in Background” is enabled you should not put another program into the foreground during the export. Otherwise the export could fail or even cause crashes.
If you connect other programs (for example Reason) via ReWire with Cubase/Nuendo the option should be disabled in order to allow a stable ReWire connection.
Generally it is recommended to enable the option only when required.