How To Fix C%021 - Enter a unique reference object

SAP Error Message - Details

• Message type: E = Error

• Message class: C% -

• Message number: 021

• Message text: Enter a unique reference object

Self-Explanatory Message

Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.

To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.

Unfortunately, there isn't any extra information in this error notice.

What else can you do?

First, use our AnswerBot below to get a possible cause and solution (requires a premium subscription).

Also, review the in-depth Common Questions & Answers listed below; you could discover a solution there or be able to connect with others who have faced similar challenges.

You can also try searching the SAP support portal (support.sap.com) but you need a special user ID to access it. It is possible that an SAP support note exists that provides additional details about the mistake or even steps for fixing it.

Smart SAP Assistant

• What is the cause and solution for SAP error message C%021 - Enter a unique reference object ?

  The SAP error message C%021, which states "Enter a unique reference object," typically occurs in the context of creating or managing cost objects, such as internal orders, projects, or cost centers. This error indicates that the system requires a unique identifier for the reference object you are trying to enter, but the value provided is either duplicated or not valid.
  Causes:
  
  Duplicate Entry: The reference object you are trying to enter already exists in the system, and SAP requires a unique identifier.
  Incorrect Input: The input format may not meet the system's requirements, leading to the inability to recognize it as a unique object.
  Configuration Issues: There may be configuration settings in the SAP system that enforce uniqueness for certain fields or objects.
  
  Solutions:
  
  Check Existing Objects: Verify if the reference object you are trying to enter already exists in the system. You can do this by searching for the object in the relevant transaction or using the appropriate report.
  Use a Unique Identifier: If the object already exists, consider using a different identifier that is unique. Ensure that it adheres to the naming conventions and formats required by your organization.
  Review Input Format: Ensure that the input you are providing matches the expected format. Check for any leading or trailing spaces, special characters, or incorrect data types.
  Consult Configuration: If you suspect that the issue is related to system configuration, consult with your SAP administrator or technical team to review the settings related to reference objects and uniqueness constraints.
  Error Documentation: Refer to SAP documentation or support notes for additional context on the error message and any specific recommendations provided by SAP.
  
  Related Information:
  
  Transaction Codes: Depending on the context, you may be using transaction codes like KO01 (Create Internal Order), CJ20N (Project Builder), or others related to cost object management.
  SAP Notes: Check SAP Notes for any known issues or patches related to this error message.
  User Authorization: Ensure that you have the necessary authorizations to create or modify the reference object in question.
  
  If the problem persists after trying the above solutions, it may be beneficial to reach out to your SAP support team for further assistance.