How To Fix 00121 - SAP GUI does not support strings (variable length types)

SAP Error Message - Details

• Message type: E = Error

• Message class: 00 -

• Message number: 121

• Message text: SAP GUI does not support strings (variable length types)

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.

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Smart SAP Assistant

• What is the cause and solution for SAP error message 00121 - SAP GUI does not support strings (variable length types) ?

  The SAP error message "00121: SAP GUI does not support strings (variable length types)" typically occurs when there is an attempt to use variable-length string types in a context where the SAP GUI does not support them. This can happen in various scenarios, such as when working with ABAP programs, function modules, or when interfacing with external systems.
  Cause:
  
  Variable-Length Strings: The error is primarily caused by the use of variable-length string types (like STRING or XSTRING) in the ABAP code or in the data being processed. The SAP GUI may not be able to handle these types correctly, especially in older versions or specific configurations.
  Data Transfer Issues: If data is being transferred between different systems or components (like RFC calls), and one of the systems is using variable-length strings, it can lead to this error.
  Incompatible Data Types: The error can also arise if there is a mismatch in expected data types between the SAP GUI and the backend system.
  
  Solution:
  
  Change Data Types: If you have control over the ABAP code, consider changing the variable-length string types to fixed-length character types (like CHAR or NCHAR). This can help avoid the issue with the SAP GUI.
  Use Compatible Data Structures: Ensure that the data structures being used are compatible with the SAP GUI. Avoid using variable-length types in the data structures that are being passed to or from the GUI.
  Update SAP GUI: If you are using an older version of the SAP GUI, consider updating to the latest version, as newer versions may have better support for various data types.
  Check RFC Settings: If the error occurs during remote function calls (RFC), check the settings and ensure that the data types being used are compatible across the systems involved.
  Debugging: Use debugging tools to trace where the error occurs in the code. This can help identify the specific variable-length string that is causing the issue.
  
  Related Information:
  
  SAP Notes: Check SAP Notes for any specific patches or updates related to this error. SAP frequently releases notes that address known issues and provide solutions.
  Documentation: Review the SAP documentation for the specific version you are using to understand the limitations and supported data types in the SAP GUI.
  Community Forums: Engage with SAP community forums or support channels to see if others have encountered similar issues and what solutions they have found.
  
  By addressing the use of variable-length strings and ensuring compatibility between the SAP GUI and the backend systems, you can resolve the error message 00121 effectively.