just found this thread from 2009, but, thought I'd post anyway. I had this issue with my c240- front drivers side corner of roof was lifted slightly higher that the rest of it, worried about leaks and just wanted it closed. it would pop open using the switch, but, would not slide open, if I closed it - no problem with switch but front left corner would not seal (stayed high). I popped it open , held onto the glass from outside and pulled back on it, this created some space between the glass and the front of the opening. I found that there is an "L" shape guide that runs along the frame of the opening when roof slides back and forth, that was on the top part of the rail instead of the underside, so, in the closed position it was causing the glass to sit high on that side. I was able to maneuver it underneath the rail where it belonged and then able to close the roof and slide it open (partially), it got jammed 1/2 way open. I found part of a metal bracket stuck in the track, still not sure where it came from but seems like that caused the glass to come off track. I lubed and tested it a few dozen times, checked the opposite side to try to identify the piece I found, but could not identify it. good news is the roof works now but I still don't know where the piece came from that caused the problem. I have photos of the roof in open position and the part I found. will post when I can.

 

https://mbworld.org/forums/c-class-w...-thread-2.html