Wolfmix

Sorry. I am not a professional. This link I was directed to is about projects. I've search manuals, mini lessons, youtube. My question is—I came in one day to use the system. On the preset page, some presets were missing. How can I restore them?

Saw a previous post about this, but the person figured it out and didn't say how. I use the system in a community center. Many people have access to it. Came in one day to find some presets were gone. How do I restore them? From now on I will lock the system. Appreciate any help.