Hi. I own and use an 1818vsl too. From your question, I presume you are using UC as the driver. What you need to do is uninstall UC and then install Audiobox VSL v1.3. This driver has the virtual mixer and you can then adjust the levels. The driver is on the downloads page for the interface on the Presonus site. While you are at it, I wouldn't bother re-installing a later driver as you will lose the virtual mixer facility; and there are no benefits for this interface I am aware of. Mine works flawlessly with v1.3 on Win7. It is also stated to be compatible with Win10. Hope this helps.