You mean the interface? When you enable Audio Only Mode it disables features in MC, causing the startup view to change. In MC Options > Startup > change Location to Last Location and Mode to Last Exit View and see if that helps - it should reopen to the last view you used.
Otherwise, I'm having trouble understanding what exactly you mean, because the Audio Only Mode setting is saved correctly here in my tests but it sounds you're referring to something else, one of the audio views instead. Screenshots would greatly help.