Hi I've recently tried to update to the latest version of Lightroom. I updated on creative cloud and when I went to open Lightroom CC my computer went to update catalog file format. But it has frozen and is not doing anything. I can now not get into Lightroom which is causing me serios stress. Any help would be very greatfully appreciated. Mark
Try to open LrC while holding down the Ctrl key (Opt key on Mac). It will open a dialog to select a catalog or start a new one. I'd try to select the old catalog again and start the catalog upgrade again.