Groups

Hi! I am a new endnote user and have only 67 references total/ 67 unfiled references. I am trying to sort them now into groups. When I made three new groups and tried to select and drag items across. Endnote quits unexpecedly and when I re start it things have changed. The groups are now called Unfiled groups and lost their names. They are called just new groups with no references in them. Does anyone know what I am doing wrong?