Btukfyl

I'm using a list with itemize as follows:

begin{itemize}

  item SuperTopic 1      

    begin{itemize}

      only<2->{item SubTopic 1}

      only<3->{item SubTopic 2}

    end{itemize}

  item SuperTopic 2                

end{itemize}

This produces an error saying that I do have an empty list (the 2nd level itemize), although visually works fine.

I'm not using item<2-> because I don't want to occupy that space in the first slide.

Is there a way to prevent the error?

Well, given you'd like to not have the whole sublevel of itemize as the overlays unfold, you could use overlays also on the environment call.

documentclass{beamer}



begin{document}



begin{frame}

  frametitle{Title}



  begin{itemize}

  item SuperTopic 1

    only<2->{begin{itemize}}

      only<2->{item SubTopic 1}

      only<3->{item SubTopic 2}

    only<2->{end{itemize}}

  item SuperTopic 2

  end{itemize}



end{frame}



end{document}

But this is a somewhat fragile construction, you can easily end up with an inconsistent structure, if you get your overlays wrong.