I know there was mention of this on here about a year ago when I read some postings. (We are still using 2007.) The problem is happening again though so this time I'm asking the question. When sketching, every so often, a tiny line will appear in the corner of a sketch which prevents the sketch from being extruded. When you zoom right in to the corners, there is a tiny diagonal line coming off the corner which needs to be deleted. Has the answer to this one been found since I was last on here?