Don't close the command window, CubeItMod will close it at the end of process and will send you a message to show you the parameters used into your file.
The time required to close the window depend on the file size.
Don't use blanks into the file name when you save or Kisslicer will not give the filename to CubeItMod and you'll stay blocked with the black window.
Before retry check on the right of the windows bar if CubeItMod is still open, if so close it before save another time.