Error: The selected field is a required field and cannot be deleted

Error Message

In some instances, when an attribute table is acquired from an external source, some fields may no longer be needed. When attempting to delete the field, the following error is returned:

Error:
The selected field is a required field and cannot be deleted.

Cause

This error occurs because the Field IsRequired option is checked when creating the field using the Add Field tool. Once a field is set as required, new records must contain a value for the field. Required fields are permanent by design and cannot be deleted.

Solution or Workaround

A workaround is to export the attribute table using the Feature Class To Feature Class tool, and remove the field in the Field Map section, as follows:

1. In ArcMap, navigate to ArcToolbox > Conversion Tools > To Geodatabase > Feature Class To Feature Class.
2. In the Feature Class To Feature Class tool dialog box, select the feature class with the required field as the Input Features.
3. Select the Output Location and the Output Feature Class.
4. Select the required field in the Field Map section and click the X button to remove the field. For more information, refer to the following ArcGIS Web Help: Using the field mapping control.
   
5. Click OK. The new feature class is added to the Table Of Contents.

Note:
Exporting the feature class to a geodatabase from the Catalog window also opens the Feature Class to Feature Class tool dialog box.
Using the Feature Class to Feature Class tool creates a new instance of the attribute table, and the required field in the original attribute table is not removed.

Related Information

• ArcMap Help: Using the Feature Class To Feature Class tool
• ArcMap Help: Feature Class To Feature Class