How To Fix AA377 - Posting not possible in company code & owing to legacy data transfer

AA377 - Overview

• Message type: E = Error

• Message class: AA - Messages for Asset Accounting

• Message number: 377

• Message text: Posting not possible in company code & owing to legacy data transfer

What causes this issue?

You want to post a transaction in a company code that still has legacy
data transfer status.
Asset transactions are <ZH>not</> possible when legacy data is being
transferred in a production company code (that is, <ZH>not</> a test
company code).

System Response

The system terminates the update.

How to fix this error?

Check if you are posting to the correct company code.
If you really want to post transactions in the company code entered, in
Customizing under <LS>Asset Accounting -> Asset Data Transfer ->
Parameters for Data Transfer -> Define Transfer Date and Additional
Parameters</>, you must select one of the following statuses for the
company code:
Company code is in test status (transactions and legacy data transfer
are allowed in parallel) or
Company code is in production status, legacy data transfer is complete
(transactions are allowed)

Error message extract from SAP system. Copyright SAP SE.

AA377 - Details

• The SAP error message AA377, which states "Posting not possible in company code & owing to legacy data transfer," typically occurs in the context of asset accounting when there are issues related to the transfer of legacy data into the SAP system. This error can arise during the posting of asset transactions, particularly when the system detects inconsistencies or issues with the legacy data.
  Causes:
  
  Incomplete Legacy Data Transfer: The legacy data for assets may not have been fully or correctly transferred into the SAP system.
  Incorrect Configuration: The company code settings or asset accounting configuration may not be set up correctly to handle legacy data.
  Missing or Incorrect Master Data: The asset master data may be incomplete or incorrect, leading to issues during posting.
  Posting Period Issues: The posting period may be closed or not open for the transaction being attempted.
  Asset Class Issues: The asset class may not be properly defined or may not