How To Fix MM661 - BUoM in additional data of the class must be convertible to material BUoM

SAP Error Message - Details

• Message type: E = Error

• Message class: MM - Messages for material master maintenance and Customizing

• Message number: 661

• Message text: BUoM in additional data of the class must be convertible to material BUoM

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.

What else can you do?

First, use our AnswerBot below to get a possible cause and solution (requires a premium subscription).

Also, review the in-depth Common Questions & Answers listed below; you could discover a solution there or be able to connect with others who have faced similar challenges.

You can also try searching the SAP support portal (support.sap.com) but you need a special user ID to access it. It is possible that an SAP support note exists that provides additional details about the mistake or even steps for fixing it.

Smart SAP Assistant

• What is the cause and solution for SAP error message MM661 - BUoM in additional data of the class must be convertible to material BUoM ?

  The SAP error message MM661 ("BUoM in additional data of the class must be convertible to material BUoM") typically occurs in the context of material master data management, particularly when dealing with units of measure (UoM) in the classification of materials. This error indicates that there is an issue with the conversion between the base unit of measure (BUoM) of the material and the unit of measure defined in the classification data.
  Cause:
  
  
  Incompatible Units of Measure: The unit of measure defined in the classification data (e.g., in the classification system or class type) is not compatible with the base unit of measure of the material. For example, if the material's BUoM is in kilograms, but the classification data is in grams, the system cannot convert between these two units without a proper conversion factor.
  
  
  Missing Conversion Factors: There may be no conversion factors defined for the units of measure involved. SAP requires that all units of measure used in the classification system have a defined conversion to the material's base unit of measure.
  
  
  Incorrect Configuration: The configuration of the material master or the classification system may be incorrect, leading to mismatches in expected units of measure.
  
  
  Solution:
  
  
  Check Unit of Measure Settings:
  
  Go to the material master record and check the base unit of measure (BUoM).
  Review the classification data for the material and ensure that the units of measure used there are compatible with the BUoM.
  
  
  
  Define Conversion Factors:
  
  If the units of measure are different, ensure that conversion factors are defined in the system. You can do this in the SAP system by navigating to the relevant configuration settings for units of measure.
  
  
  
  Adjust Classification Data:
  
  If necessary, adjust the classification data to use a unit of measure that is compatible with the material's BUoM.
  
  
  
  Review Class Type Settings:
  
  Check the class type settings in the classification system to ensure that they are correctly configured to allow for the necessary conversions.
  
  
  
  Consult Documentation:
  
  Refer to SAP documentation or help resources for specific guidance on managing units of measure and classification data.
  
  
  
  Related Information:
  
  Transaction Codes: You may need to use transaction codes such as MM02 (Change Material), CL02 (Change Class), or CL01 (Create Class) to manage material and classification data.
  SAP Notes: Check for any relevant SAP Notes that may address specific issues or bugs related to this error message.
  User Roles and Authorizations: Ensure that you have the necessary authorizations to make changes to material master data and classification settings.
  
  By following these steps, you should be able to resolve the MM661 error and ensure that your material and classification data are correctly aligned in terms of units of measure.