Our office is having the same problem (no snapping in symbols), regardless of the combination of constraints that are selected. I have "Snap to Object", and "Smart Cursor Cues" on, but my symbols are still virtually unusable because I can not place them in their correct locations without snaps.
This problem happens on all of our drawings on multiple computers, and is a major issue with symbols. Is there an update past VW10.1.0 that will resolve this? Any solution (no matter how unorthodox) would be greatly appreciated. Thanks.