How To Fix DMC_GENERAL478 - Field &3 in Table &1 has unknown datatype &4 (RFC dest &2)

SAP Error Message - Details

• Message type: E = Error

• Message class: DMC_GENERAL - MWB: General Messages

• Message number: 478

• Message text: Field &3 in Table &1 has unknown datatype &4 (RFC dest &2)

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 DMC_GENERAL478 - Field &3 in Table &1 has unknown datatype &4 (RFC dest &2) ?

  The SAP error message DMC_GENERAL478 indicates that there is an issue with a field in a specific table that has an unknown datatype. This error typically arises in the context of data migration or data transfer processes, particularly when using the Data Migration Cockpit (DMC) or similar tools.
  Cause:
  
  
  Unknown Datatype: The field in the specified table has a datatype that is not recognized by the system. This could be due to:
  
  A custom field or table that has not been properly defined in the system.
  A mismatch between the source and target systems, where the source system has a datatype that does not exist in the target system.
  An issue with the RFC (Remote Function Call) destination configuration, which may not be able to interpret the datatype correctly.
  
  
  
  Data Model Changes: If there have been recent changes to the data model (e.g., new fields added, datatypes changed), the DMC may not be aware of these changes.
  
  
  Transport Issues: If the table or field was recently transported from one system to another, there may have been issues during the transport process that led to the datatype not being recognized.
  
  
  Solution:
  
  
  Check Table and Field Definitions: Verify the definitions of the table and field in both the source and target systems. Ensure that the datatype is correctly defined and exists in both systems.
  
  
  Update RFC Destination: Ensure that the RFC destination is correctly configured and that it can access the necessary data types. You may need to check the connection settings and ensure that the target system is reachable.
  
  
  Data Migration Cockpit Configuration: Review the configuration of the Data Migration Cockpit. Ensure that the mapping of fields and datatypes is correctly set up.
  
  
  Recreate or Adjust the Field: If the field is custom, consider recreating it with a recognized datatype or adjusting the existing field to use a standard datatype.
  
  
  Check for Updates: Ensure that both the source and target systems are updated to the latest support packages or patches, as this may resolve compatibility issues.
  
  
  Consult SAP Notes: Look for relevant SAP Notes that may address this specific error message or provide guidance on similar issues.
  
  
  Related Information:
  
  SAP Documentation: Refer to the official SAP documentation for the Data Migration Cockpit and data transfer processes for more detailed guidance.
  SAP Community: Engage with the SAP Community forums to see if other users have encountered similar issues and what solutions they found effective.
  SAP Support: If the issue persists, consider reaching out to SAP Support for assistance, providing them with the error details and context.
  
  By following these steps, you should be able to identify the root cause of the DMC_GENERAL478 error and implement a suitable solution.