I have problems with a point data layer in ArcGIS (9.3). An additional symbol has appeared on some of the points within the layer which were recently created and checked-in from ArcPad. This additional symbol cannot be edited and has been placed on top of another symbol which I can edit normally using layer properties. I would like to remove the additional symbol and retain a single editable symbol for each point. Any advice on how to do this would be gratefully received.
Edit #1: I have checked the map as suggested in the answer below and have multiple symbols on single points in a single layer. How do I remove the multiple symbols and return to a single editable symbol?
Edit #2: The screenshot below shows an extract from the map (of trees). The blue circle is the editable symbol covering all points in the layer. The green circle is the additional non-editable symbol which has appeared for the most recently checked-in points. I have selected two points labelled Betula and Quercus. The selected point labelled Quercus has an additional green circle symbol, although that is not shown due to the selection highlighting.