I have received a D type visa to study in Czech Republic. It starts on September 11th. But I would like to go there earlier. When applying to a C type (toursitic) Schengen visa, the issuing country obviously wants me to come back to my country after the expiry date.
What happens if I have a C type visa from another Schengen country from August 20th to September 12th? Should I as well come back and go again, or can I just activate my D type by the alien police and stay there after expiration of my C type visa?
A slightly related problem that I am facing is, is it possible to have a C type visa starts before a D type?