Changed fourCC of an FLV file and it disappeared

I don’t know what happened, I had an FLV file I changed the FourCC using avicc to get the file to show up in Vegas and then all of a sudden the file was just gone I mean like it never existed. I tried Recuva to see if it was deleted, I searched hidden files, I even tried reopening it in avicc but nothing, the file just disappeared, what can I do to get it back?