Did you think about searching for find and delete duplicate features if the problem is solely for identical features. There are many python scripts for this. Some are : [1][1], [2][2], [3][3]. [1]: http://arcscripts.esri.com/details.asp?dbid=14014 [2]: http://arcgispro.blogspot.com/2012/04/how-to-delete-duplicates-features-in.html [3]: http://gis.stackexchange.com/questions/26921/remove-spatially-duplicate-features-using-modelbuilder