I started the jit on dev machine and found a clue that this exection is win32exception and raising in the Windows Application (Form Appliction) which is being started by this service. Here is the what I saw, but I am still not sure why this error comes after 24 processes are started without such error. Any comment? Errors: 1. An unhandled exception of type 'System.ComponentModel.Win32Exception' occurred in system.windows.forms.dll Additional information: The parameter is incorrect And 2. An unhandled exception of type 'System.ComponentModel.Win32Exception' occurred in system.windows.forms.dll Additional information: Error creating window handle.