How To Fix NAA391 - Overflow, calc. error for conversion factors from unit &1 to &2

SAP Error Message - Details

• Message type: E = Error

• Message class: NAA - Subsequent settlement (Purchasing)

• Message number: 391

• Message text: Overflow, calc. error for conversion factors from unit &1 to &2

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message NAA391 - Overflow, calc. error for conversion factors from unit &1 to &2 ?

  The SAP error message NAA391, which indicates an "Overflow, calc. error for conversion factors from unit &1 to &2," typically occurs during the conversion of measurement units in SAP, particularly in the context of materials management or production planning. This error suggests that there is an issue with the conversion factors defined between the two units of measure.
  Cause:
  
  Invalid Conversion Factors: The conversion factors between the two units of measure may not be defined correctly or may be missing.
  Overflow in Calculation: The calculation of the conversion factor may result in a value that exceeds the maximum limit that can be handled by the system, leading to an overflow error.
  Data Type Limitations: The data types used for storing conversion factors may not be sufficient to handle the values being processed.
  Unit of Measure Configuration: There may be issues in the configuration of the units of measure in the system, such as incorrect settings in the unit of measure table.
  
  Solution:
  
  
  Check Conversion Factors: Review the conversion factors defined for the units of measure involved. Ensure that they are correctly set up in the system.
  
  You can check this in the SAP transaction code CUNI (Unit of Measure Conversion).
  
  
  
  Review Unit of Measure Configuration: Ensure that the units of measure are correctly configured in the system. This includes checking the settings in the unit of measure table (T006) and ensuring that the units are properly defined.
  
  
  Data Type Review: If the conversion factors are calculated dynamically, ensure that the data types used in the calculations can handle the expected range of values. You may need to adjust the data types in the relevant ABAP programs or function modules.
  
  
  Test with Different Values: If possible, test the conversion with different values to see if the error persists. This can help identify if the issue is related to specific values or a broader configuration problem.
  
  
  Consult SAP Notes: Check the SAP Support Portal for any relevant SAP Notes that may address this specific error message. There may be patches or updates that resolve known issues related to unit conversions.
  
  
  Contact SAP Support: If the issue persists after checking the above points, consider reaching out to SAP Support for further assistance. Provide them with detailed information about the error, including the specific units involved and any relevant transaction codes.
  
  
  Related Information:
  
  Transaction Codes: 
  
  CUNI: Unit of Measure Conversion
  CUNI: Maintain Units of Measure
  
  
  Tables:
  
  T006: Units of Measure
  T006A: Units of Measure (Language-dependent texts)
  
  
  Documentation: Review SAP documentation related to unit of measure management and conversion factors for additional insights.
  
  By following these steps, you should be able to identify and resolve the cause of the NAA391 error in your SAP system.