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

00121 - Overview

• 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.

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.

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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