Yesterday whilst cleaning my car I put the roof down whilst doing this it was struggling to go down tried putting it back up and it was really struggling is there a way to manually lower your roof ?
But yes, you can open it manually
http://www.z4-forum.com/howto/2005_Z4.pdf
see page 23
it about closing it manually, but same thing works for opening it.. just open the roof clamps first by pressing the roof open button.