For some reason, when I opened my pipe elbow model which was done in 2009 using a 2011 version. Some of the sketches will not update their relations, creating dangling points and lines. I am not sure if this is a common problem when using the newer 2011 version or not. The model is a cylinder sheetmetal piece, and one of the 2 flat side surface of the cylinder seems not be able to keep existing relations when i open the model with 2011 version. If anyone knows a ppossible solution to this problem besides redoing all the relations, that would be very helpful, thanks.