How To Fix GB123 - Rule must begin with a letter

SAP Error Message - Details

• Message type: E = Error

• Message class: GB - Messages used by the Boolean code generator

• Message number: 123

• Message text: Rule must begin with a letter

What causes this issue?

You have attempted to create a subrule with a name that does not begin
with a standard alphabetic character. The first digit may not be
numeric. Only characters belonging to the international character set
are supported.
'ABCDEFGHIJKLMNOPQRSTUVWYXYZ'

System Response

None

How to fix this error?

Choose a different name.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message GB123 - Rule must begin with a letter ?

  The SAP error message "GB123 Rule must begin with a letter" typically occurs in the context of defining or configuring rules in SAP, particularly in areas like validation, substitution, or other custom rules where a naming convention is enforced.
  Cause:
  The error indicates that the rule name you are trying to create or modify does not start with an alphabetic character (A-Z, a-z). This is a requirement in SAP to ensure that rule names are valid and follow the naming conventions set by the system.
  Solution:
  To resolve this error, you should:
  
  
  Check the Rule Name: Ensure that the rule name you are entering starts with a letter. For example, instead of using a name like "123Rule" or "_Rule", you should use "Rule123" or "A_Rule".
  
  
  Modify Existing Rules: If you are trying to modify an existing rule that has an invalid name, you will need to rename it to comply with the naming convention.
  
  
  Follow Naming Conventions: Familiarize yourself with the naming conventions used in your SAP environment. Typically, rule names should be descriptive and start with a letter.
  
  
  Test Changes: After making the necessary changes, try to save or activate the rule again to see if the error persists.
  
  
  Related Information:
  
  SAP Documentation: Refer to the official SAP documentation for guidelines on naming conventions and rules in the specific module you are working with (e.g., Financial Accounting, Controlling, etc.).
  Transaction Codes: Depending on where you are encountering this error, you may be using specific transaction codes (like OB28 for validation rules or OBBH for substitution rules). Make sure you are familiar with the relevant transaction codes and their functionalities.
  SAP Community: If you continue to face issues, consider reaching out to the SAP Community or forums where other users may have encountered similar problems.
  
  By ensuring that your rule names adhere to the required format, you should be able to resolve the GB123 error effectively.