How To Fix DT401 - Customer and SAP Includes not allowed for table type &

SAP Error Message - Details

• Message type: E = Error

• Message class: DT - Table activation (incl. indexes)

• Message number: 401

• Message text: Customer and SAP Includes not allowed for table type &

What causes this issue?

Customer-specific include tables may only be included in transparent
tables and in structures.
Customer-specific includes are included tables in the namespace CI_.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Check if the tables can be made transparent. Otherwise the
corresponding include line must be removed from the fields and possible
replaced by the included fields.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message DT401 - Customer and SAP Includes not allowed for table type & ?

  The SAP error message DT401 indicates that there is an issue with the definition of a table type in ABAP Dictionary. Specifically, it states that "Customer and SAP Includes not allowed for table type &". This error typically arises when you attempt to use a customer or SAP include in the definition of a table type, which is not permitted.
  Cause:
  
  Table Type Definition: The error occurs when you try to include a structure or a table type that is defined in a customer or SAP include in the definition of a table type. SAP restricts the use of includes in table types to maintain consistency and integrity in data structures.
  Inappropriate Use of Includes: If you are trying to create a table type that references a structure defined in a customer include or an SAP include, this will trigger the error.
  
  Solution:
  
  Remove Customer/SAP Includes: Modify the table type definition to ensure that it does not reference any customer or SAP includes. Instead, use standalone structures or types that do not rely on includes.
  Create a New Structure: If you need to use specific fields from a customer or SAP include, consider creating a new structure that directly defines the required fields without using the include.
  Check Dependencies: Review the dependencies of the table type and ensure that all referenced structures are defined correctly and do not include any customer or SAP includes.
  
  Related Information:
  
  ABAP Dictionary: The ABAP Dictionary is a central repository in SAP that defines data structures, including tables, views, and data elements. Understanding how to properly define table types and structures is crucial for avoiding such errors.
  Data Types: Familiarize yourself with the different data types in ABAP, including elementary types, structured types, and table types, to ensure proper usage.
  SAP Notes: Check SAP Notes for any specific guidance or updates related to this error message, as there may be additional context or solutions provided by SAP.
  
  If you continue to face issues, consider consulting with an SAP ABAP developer or your technical team for further assistance.