To Save a Drawing With Layer and Spatial Indexes

1. Click File menu Save As.
2. In the Save Drawing As dialog box, click Tools Options.
   
3. In the Saveas Options dialog box, under Index Type, select Layer, Spatial, or Layer & Spatial and click OK.
Note: If you are saving a partially open drawing that does not already contain layer and spatial indexes, this option is disabled.
4. Click Save.