FAQ: Are ArcView GIS 3.x attribute indexes used by ArcMap or ArcCatalog?
Are ArcView GIS 3.x attribute indexes used by ArcMap or ArcCatalog?
Attribute indexes created in ArcView GIS 3.x are not used by ArcMap or ArcCatalog.
ArcGIS offers a new attribute indexing format for shapefiles and dBASE files, which can be created from the Properties dialog box in ArcCatalog. This will produce an .atx file for each indexed field.
For a sample tool that converts ArcView GIS 3.x attribute indexes to ArcGIS 8 attribute indexes, see ArcObjects Developer Help > Contents > Samples > ArcCatalog > GxTables > Convert AV3 to AV8 Attribute Indexes.