Error: 000520 : Unexpected TopoEngine Error
In some instances, when attempting to convert a shapefile or feature class to CAD data with the Export To CAD tool, the following error message is displayed:
“000520: Unexpected TopoEngine Error.”
The error message occurs if:
(A) The input dataset is very large, with close to one million or more vertices. This may be referred to as a 'Godzilla' dataset because performing editing operations or geoprocessing on such large datasets can produce memory errors or system crashes. For more information on 'Godzillas', refer to the following ArcGIS blog post, Dicing Godzillas (features with too many vertices).
(B) There are geometry problems in the feature class. For example, the feature class contains 'NULL' geometries.
Solution or Workaround
(A) Clip the data to smaller subsets to convert the shapefile to CAD data instead of attempting to convert the dataset all at once.
(B) Run the Check Geometry tool. If geometry problems are discovered, run the Repair Geometry tool.