all of my Effects Favorites disappeared from panel

I just had this happen to me when I changed workspaces. When I changed back to my regular workspace, all my favorites were gone. Just as I was going to start rebuilding them I noticed that the search bar at the top of the window had characters in it. I deleted them and instantly all my favorites were back.

However you look at this, something is happening to your Properties folder - it has to be, because that's where all the information about everything to do with effects is stored. There are several things that can affect it; even things like an over-protective OS restoring settings can screw this up. The obvious thing though is to be logged onto your machine as a different user - even worse, without Administrator privileges. That has caught out a few before, and it's all down to what happens with Properties. Chances are though that if you can't find anything you did previously, they are gone forever - unless you saved them under a different user-name.