I had a most difficult time opening a file. I tried Find & Open and Open from the File Menu. I tried to launch the file from the Finder with no success. I tried to open the file programmatically with the OpenSecret, SetActiveDatabase, OpenSheet. Nothing seemed to work. I had not made any changes to the file since I last had it open yesterday. Memory Usage showed the file, but I could not open it from there either. Finally, I re-downloaded the file from the server and was able to OpenDatabase from the Gear icon in the Server Administration Window.