I have similar problem. I have distributed an app with all libraries, including a *.rcc external binary resource file and register it in the program. It works ok at mine but in another system where Qt is not installed, system tray icon is missing; although, the icon in task bar and window title is visible. Also, system tray icon is missing in MAC OS X. I tried to build the app with external and internal resource file, changed icon form for Win to MAC OS X but sys tray icon is still missing in both Win and Mac OS X; another system is XP Pro without Qt.