The feature's geometry could not be modified.

Error Message

Finishing a sketch(F2), or saving edits in ArcMap returns: 'The feature's geometry could not be modified.'

Cause

The attribute table contains duplicate field names.

Solution or Workaround

1. Save edits and exit from ArcMap.
2. Start ArcCatalog.
3. Navigate and select the shapefile in the Catalog tree.
4. Right-click on the shapefile and click Properties.
5. Click the Fields tab.
6. Select the duplicate field name.
   

   Click the gray button to the immediate left of the Field Name.

   
   
   
7. Press the delete button on the keyboard.
8. Click Apply, then click OK.