If you're seeing the infamous "Beachball" icon while using mInstaller, please close the app (via CMD+Q or using the Activity Monitor.app), switch to Finder, go to your Applications folder, press and hold the CMD+OPTION(ALT) keys, double-click mInstaller.app and press 'Delete Preferences' button (this will wipe its preferences and database before launching the app). Check if this persists now!