How To Fix UAS138 - Key field &1 must be displayed

SAP Error Message - Details

• Message type: E = Error

• Message class: UAS -

• Message number: 138

• Message text: Key field &1 must be displayed

What causes this issue?

For creation and processing of the object, key fields must not be
initial. The configuration tool prevents you from closing the window
because you have declared a key field as 'Invisible' without filling the
field by means of a formula. Therefore, the key field would always be
'initial'.

How to fix this error?

Assign a value to the key field declared as <LS>Invisible</> using a
formula at the time of creation (intialise or complete).

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message UAS138 - Key field &1 must be displayed ?

  The SAP error message UAS138, which states "Key field &1 must be displayed," typically occurs in the context of data entry or processing in SAP applications where a key field is required to be visible but is not currently displayed in the user interface. This can happen in various modules, particularly in those related to master data or transactional data entry.
  Cause:
  
  Field Configuration: The key field may not be configured to be displayed in the screen layout or user interface for the transaction you are using.
  Authorization Issues: The user may not have the necessary authorizations to view certain fields, leading to the error.
  Custom Development: If there are custom screens or enhancements, the key field might have been inadvertently hidden or removed from the display.
  Data Entry Errors: The user might be trying to enter data without the required key field being visible, which is necessary for the system to process the transaction.
  
  Solution:
  
  
  Check Field Status: 
  
  Go to the relevant configuration settings in the SAP system (e.g., SPRO) and check the field status group for the transaction or data entry screen. Ensure that the key field is set to "Display" or "Required."
  
  
  
  Screen Layout:
  
  If you have access to the screen layout configuration, verify that the key field is included in the layout and is set to be displayed.
  
  
  
  Authorization Check:
  
  Ensure that the user has the necessary authorizations to view the key field. This can be checked in the user roles and profiles assigned to the user.
  
  
  
  Custom Development Review:
  
  If there are custom developments or enhancements, review the code to ensure that the key field is not being hidden or removed from the display.
  
  
  
  Consult Documentation:
  
  Refer to SAP documentation or help resources for the specific transaction or module you are working with to understand the requirements for key fields.
  
  
  
  Contact Support:
  
  If the issue persists after checking the above points, consider reaching out to your SAP support team or consulting with an SAP expert for further assistance.
  
  
  
  Related Information:
  
  Transaction Codes: Depending on the context, you may be working with specific transaction codes (e.g., VA01 for sales orders, ME21N for purchase orders) where this error can occur.
  SAP Notes: Check for any relevant SAP Notes that might address this specific error message or provide additional troubleshooting steps.
  User Forums: SAP Community and other user forums can be helpful for finding similar issues faced by other users and their solutions.
  
  By following these steps, you should be able to identify the cause of the UAS138 error and implement a solution to resolve it.