Please check that all bolts are tight (the big on transmission and fixing the roof to the body).
When the screws are not tightened the roof is not working properly, once working properly, sometimes descends too quickly and hit the windshield frame, and sometimes, as in your case, does not close.

 

Be very wary about this. I tried the same thing in November and my B-pillar broke on the driver's side. As soon as I heard that thing snap, I wished I'd have been content with a manual top. Still have a manual top, but with loads of headache between November and now.

 

I do not have to unzipp the rear window because it replaced the original roof, the roof of the model 993. Looks much better. If You want i can add some pics.

 

Alfred:

Thanks for the tip and sorry for your troubles. Perhaps I will just focus on resolving the top lock fault issue and not try to get the cab back to full automation. The B pillar snap story is all too common here on Rennlist and one that I wish to avoid.

 

Have you tried just pressing down on the top while someone holds the button to close? The switches above the windshield may not both be getting triggered. Can happen if the alignment is off slightly. It's worth a quick check.