How To Fix MC590 - Target field may only be assigned once

SAP Error Message - Details

• Message type: E = Error

• Message class: MC - Aggregate: views, matchcodes, lock objects

• Message number: 590

• Message text: Target field may only be assigned once

What causes this issue?

You have defined more than one target field. In order to be able to use
matchcodes as an online utility, you must set up a connection between a
matchcode field and a screen field. This connection is defined with
the target field. In a matchcode selection, the value of this field is
transferred to the screen field.

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?

Mark only one field as target field.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message MC590 - Target field may only be assigned once ?

  The SAP error message MC590 ("Target field may only be assigned once") typically occurs in the context of data processing or data transfer within SAP, particularly when working with data extraction or reporting in the Material Management (MM) module or similar areas. This error indicates that there is an attempt to assign a value to a target field more than once, which is not allowed.
  Cause:
  
  Duplicate Assignments: The most common cause of this error is that the same target field is being assigned multiple times within a single processing block or logic. This can happen in ABAP programs, data transfer routines, or during the execution of certain transactions.
  Incorrect Logic: The logic in the program or configuration may inadvertently lead to multiple assignments to the same field.
  Data Source Issues: If the data source is providing duplicate records or if there are issues with the data extraction logic, it may lead to this error.
  
  Solution:
  
  Review the Code/Logic: Check the ABAP code or the configuration where the error is occurring. Look for any instances where the same target field is being assigned multiple times. Ensure that each target field is assigned only once within the relevant scope.
  Use Conditional Logic: If there are conditions under which the field should be assigned, ensure that the logic is structured to prevent multiple assignments. Use IF statements or other conditional checks to control when assignments occur.
  Debugging: If you are unable to find the issue through code review, consider using the debugging tools in SAP to step through the execution and identify where the multiple assignments are happening.
  Data Validation: Ensure that the data being processed does not contain duplicates or unexpected values that could lead to multiple assignments. Validate the data source and the extraction logic.
  Consult Documentation: If the error occurs in a standard SAP transaction or report, consult the SAP documentation or support notes for any known issues or updates related to the error.
  
  Related Information:
  
  Transaction Codes: Depending on where the error occurs, you may be working with transaction codes like MC.9 (Inventory Management), MC.1 (Material Analysis), or others related to reporting and data extraction.
  SAP Notes: Check SAP Notes for any specific fixes or recommendations related to the MC590 error. You can search for relevant notes in the SAP Support Portal.
  Community Forums: Consider visiting SAP community forums or discussion boards where other users may have encountered and resolved similar issues.
  
  By following these steps, you should be able to identify the cause of the MC590 error and implement a solution to resolve it.