Tree lost out of seemingly nowhere

Hi there! What happened to me was, I wanted to open Tabs Outliner as I usually do, so I clicked on the TO icon. Strangely enough though, TO didn't start up and the icon disappeared. I went to the Extensions tab and saw TO was listed as "possibly damaged". I clicked the option to repair it and the extension redownloaded and reinstalled. It worked again but all my old trees disappeared, so it looked like I had just installed a fresh new TO. Is there anything I can do to get my old tree back?