How To Fix 06016 - External document number & already assigned

06016 - Overview

• Message type: E = Error

• Message class: 06 -

• Message number: 016

• Message text: External document number & already assigned

What causes this issue?

A document with this number already exists.

How to fix this error?

Enter a number that has not yet been assigned.

Error message extract from SAP system. Copyright SAP SE.

06016 - Details

• The SAP error message "06016 External document number & already assigned" typically occurs when you are trying to assign an external document number (such as a reference number or invoice number) that has already been used in the system. This can happen in various SAP modules, such as FI (Financial Accounting) or MM (Materials Management), where unique document numbers are required for transactions.
  
  Cause:
  
  Duplicate Entry: The external document number you are trying to use has already been assigned to another document in the system.
  
  Configuration Issues: The system may be configured to enforce unique external document numbers across certain transactions.
  Data Migration Issues: If data has been migrated from another system, there may be conflicts with existing document numbers.
  
  
  Solution:
  
  
  Check Existing Document Numbers: Verify if the external document number you are trying to use is already assigned to another document. You can do this by searching in the relevant transaction or using transaction codes