This is a Logic, OMS, Virtual Node support bug. Here's what to do...*Change plug-in preset. OMS node is reset to something like "OMS Map Used". *In the Arrange or Environment window look for the instrument information on the left side. *Look below the instrument icon and change "OMS Map Used" back to the appropriate Virus node (the one that's displayed in the lower right corner of the plug-in window). *You'll have to do this every time you change a sound preset.