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What you cannot do with an S/4HANA conversion project

Most of the blogs and vast amount of documentation existing in the SAP community focuses on prerequisites, steps to follow, recommendations and advices for a successful transition to S/4HANA.  

But what about the things we cannot achieve during a conversion project? Or the things which cannot be done in a specific phase of the conversion project or afterwards, in the converted and live S/4HANA system? 

In this blog, lets analyze those aspects which cannot be achieved during or post a conversion project. 

Please note that not all the items from this blog can be found in the Simplification List or in the Readiness Check. 


1. You cannot identify all the data inconsistencies in the source system.

There are standard reports available in the ECC system for consistencies checks, which have been available for a while and most of them focus on generic checks and not checks specific for the S/4HANA conversion. In order to identify all the data inconsistencies relevant for the S/4HANA conversion, a full conversion cycle must be executed, using as recent copy of Production. This is also one of the reasons the conversion project follows an iterative approach.
One of the consistency checks reports specifically targeting S/4HANA conversion projects is provided via note 2755360 However, this report is not capturing all the data inconsistencies as the programs executed during the data migration.  


  • with note 2887318 an additional program for GL errors correction is provided. This program can be used along with note 2714344 to support pre-conversion error resolution
  • note 2896400 provides a series of consistency checks in the area of Asset Accounting, targeting specific S/4HANA conversion related errors and which can be executed in ECC environments. Note  2714344 can also be consulted for asset related errors and support the resolution.

These additional programs/ notes, increase considerably the % of data inconsistencies which can be addressed before the conversion cycle.


2. You cannot implement document splitting or a further accounting principle/ledger during the conversion project.

The conversion to S/4HANA from classic GL, is similar to the New GL migration scenario 1 – Merge of Classic GL and parts of Scenario 2 (Scenario 1 and additional merging of PCA and SPL).  The implementation of document splitting and of a further accounting principle are available after the conversion to S/4HANA, as subsequent implementation projects, starting with release 1610 – for the additional accounting principle and release 1709 for the subsequent document splitting. For additional information, including limitations, please see Implementation of a Further Accounting Principle and Subsequent Implementation of Document Splitting 


3. You cannot switch from the accounts approach for parallel valuation to the ledger approach for parallel valuation. 

This transition scenario is currently not available – not during the conversion project, nor as a subsequent project in S/4HANA. It is however a planned innovation included in the future roadmap: Easier reporting and fewer general ledger accounts as a result of transitions from parallel general ledger accounts to parallel ledgers.

The transition scenario is available only in ECC at the moment, so it can be done before the conversion project, as part of the NEW GL Migrations scenarios. For a complete list of scenarios available in ECC as part of New GL Migration, please see Migration to New General Ledger Accounting. 


4.You cannot change the relationship/assignment between existing company codes and controlling areas.

This does not include creation of a new controlling area for new legal entities or the assignment of a new Controlling Area to a company code which was not using the Controlling component before. Such project can be executed only in the ECC system, before the conversion project, with the support of the team previously called SLO and currently called DM&LT.  


5. You cannot introduce an additional currency.

As part of the S/4HANA conversion, only the existing currencies are taken over in the environment.  It is possible to introduce a new currency, after the conversion, starting with release 1809. The new currency will be available only in the General Ledger component as it will be introduced only in the Universal Journal (only table ACDOCA). All the documents will be enhanced with this additional currency and all the documents pertaining to the current fiscal year will have balance zero ensured.
As this new currency will not be available in table BSEG, it will also not be reconciled for components like Asset Accounting, Material Ledger and Controlling.

During conversion or after as part of the separate project, it is also not possible to:

  • Introduce a company code currency or a controlling area currency 
  • Introduce a currency type for Transfer Pricing 
  • Convert an existing currency type 

For these specific requirements, it is still possible to execute a project in the ECC system with the support of the team previously called SLO and currently called DM&LT.  For additional information, please check SAP Help or note 2334583.  


6. You cannot use a combination of accounts approach and ledger approach for parallel valuation.

In ECC, it was possible to use such set up. In order to be able to use New Asset Accounting, which is a pre-requisite for S/4HANA, you must map the parallel valuation in New Asset Accounting with either ledger approach or accounts approach in the General Ledger application. 


7. You cannot use alternative fiscal year variants with different “beginning/end dates” when using the ledger approach for parallel valuation, for the representative ledgers in a ledger group.

This is a requirement for New Asset Accounting. Please check note 2220152 for a work-around and also the restrictions from note 844029. 


8. You cannot share the same chart of depreciation for company codes with different ledgers assignment or different currencies assignment.

This was possible in Classic Asset Accounting but not possible in New Asset Accounting, as GL and Asset sub-ledger will be completely reconciled and in sync. As a solution, you can create a new Chart of Depreciation and change the assignment of the company code to the new chart of depreciation. In order to achieve this, please raise an OSS incident with SAP Support. There is a pilot available for such requests.  


9. You cannot use the same chart of depreciation, for new company codes created after conversion, where a Parallel Ledger in source system has different currencies than the Leading Ledger.

In ECC, it was possible to have a Parallel Ledger with a different currency assignment than the Leading Ledger. In S/4HANA, the non-leading ledgers inherits the parallel currencies from the Leading Ledger. This might require an additional chart of depreciation, as the migrated ones cannot be used (it will not have the depreciation area required for the additional parallel currency in the non-leading ledger). 


10. You cannot do a partial Finance data migration – migrate selected company codes, ledgers or partial transactional data.

In case certain company codes are not required from business point of view, in order to disable some configuration checks during conversion, you can mark them as ‘‘template‘‘, as per the note 2159452.You can also consider deleting a non-leading ledger, in specific business contexts. You will have to open an OSS incident with SAP Support to get access to a pilot note. For selective data migration from ECC to an already LIVE S/4HANA OP system, please see  the scenario Company Code Specific Conversion to S/4HANA with details in the note 2522155. This scenario can be executed only with the involvement of the team previously called SLO and currently called DM&LT. 



For a smooth transition to S/4HANA, carefully consider what is the level of transformation you want to achieve, what is your current set up in the source ECC system and what are the current conversion tools and programs designed to do. A conversion project could be a great experience and bring lot of simplifications for your business and customers, given the right expectations are set.

Let me know what you think in the comments below!



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  • Hello,


    Great article, first of all!

    That means, if I have a customer, for example, having classic-GL, but wanting to switch to ledger approach, the only possibility would be a new-GL implementation project (ledger approach) before transition to S/4HANA, right?

    Or, not doing a conversion at all, but start new, greenfield.



    Daniel N.

    • Hello Daniel,

      Yes, if the customer is having classic GL, is using the accounts approach for parallel valuation and they want to transition to the ledger approach in S/4HANA, the only option currently available is to do a New GL Migration project before the conversion or do a greenfield project of course.

      I am glad to hear you found the article helpful.


      Kind regards,

      Sorina Ciobanu

      • Hi Sorina,


        Thank you for the quick answer.

        I was thinking about and also came in discussion on the same customer: Central Finance.

        What do you think? Would it be a good approach for the same customer above?


        In my opinion, Central Finance is not an ideal approach today, because S/4 is already mature enough. Why do invest in Central Finance when you can do directly S/4?

        Maybe this would have been a feasible solution few years ago, in 2012-2016, but now, I don´t think so.

        By the way, this customer, has a pretty complex Logistic construct, and the landscape consist of only SAP ERP, without other non-SAP ERP systems or other Applications.


        What is your opinion?


        Kind regards/O zi buna!


        • Hi Daniel,

          Thank you for your question. It is in fact quite a relevant question nowadays.

          S/4HANA has been around for the last 5 years and it is of course more mature and includes more innovation with each new release. In the same time, Central Finance is an adoption solution using S/4HANA as basis so from feature point of view they would have the same level of maturity.

          As a transition scenario to S/4HANA, if the customer has only one SAP instance,  we would normally recommend to first evaluate the standard transition scenarios to SAP S/4HANA- based on of course what is more important from business point view for the customer and what can be achieved in the customer’s available timeline:

          • System conversion
          • New implementation
          • Selective data transitions

          In the same time, it is possible to use also Central Finance to do a switch from source system Classic GL to a target S/4HANA system where the Ledger approach is used.This is not a out-of-box solution, but a custom solution, and one that many customers employ, and it does derive additional benefits at a later stage. This would mean a custom solution where GL accounts from the source system will be mapped to be re-posted to the target system (ledger, ledger group, account etc.)

          You mention that customer only has SAP system(s) in their landscape. A heterogenous landscape is a strong indicator and provides for a compelling use case for Central Finance- one of the main use cases of Central Finance is to run one central platform for corporate finance across distributed landscapes.

          You also mentioned the complex logistic processes in source. This indeed is not provided as an out of the box solution by SAP, but quite few customers have started their journey towards S/4HANA by implementing Central Finance as the foundation and are now starting the delta migration of the other processes (incl. Logistics) to the target system. Central Finance offers an alternative deployment option to adopt S/4HANA with significantly reduced risk and a step by step approach. If a customer is willing to transform financial data and processes at a faster pace, but also in an incremental phased approach, then Central Finance is an alternative. This could mean Logistics processes will be migrated at a later stage – a type of Lift & Shift- so this approach will have to be carefully analysed and planned by the customer and project team.

          For more information about Central Finance, see also the below blog:


          Kind regards,



  • Great article! Unfortunately, we didn't now read this earlier.

    In an S/4HANA conversion project this year, we encountered the issue of No.7:

    "7. You cannot use alternative fiscal year variants with different “beginning/end dates” when using the ledger approach for parallel valuation, for the representative ledgers in a ledger group."

    In the early project planning phase, the project team did not notice this issue until project starts (the first conversion cycle). And this impact a lot to the project: New GL w/ scenario 7 execution, unexpected New GL migration service cost,  and historical data handling... It was a nightmare..

  • Hi Sorina

    I found this article very useful. We have to perform migration from ECC 6.0 to S4H 2020. So I have following queries -

    1. Which report should be used for pre-check in AA, GL? Should we use RASFIN_MIGR_PRECHECK or FI_AA_CORR*, FI_CORR* as mentioned in note 2896400 & 2887318 ?
    2. Customer is not using New GL, and there is no business requirement for Parallel ledgers, Segment reporting etc. Can we safely migrate to S4H w/o New GL Migration ? During FI configuration in S4H migration project, Is it necessary to do basic New GL configuration ??



    • Hello Kapil,

      Happy to hear you found the article useful.

      Please see below the answers to your questions:

      1. The pre-checks are included in the SI check- so they will be automatically executed. Please check the attachment from note 2332030 - Conversion of accounting to SAP S/4HANA - SAP ONE Support Launchpad for additional details.
      2. During the conversion, New GL will be technically activated. You do not have to configure additional ledgers or document splitting. You can later implement an additional accounting principle or document splitting as separate projects in S/4HANA.

      Kind regards,


      • Hi Sorina

        Thanks for your clarification.

        Until version 17xx, we had FI specific pre-check report (RASFIN_MIGR_PRECHECK) and it seems now everything is included in SI Check. But SI check does it for complete system, and not just for FI. It takes lot of time, and I may need to execute FI pre-check couple of times. Hence I was looking for FI pre-check report.

        After SI check, should we execute FIN_AA_CORR_RECON & FIN_AA_CORR_DISPLAY, FIN_CORR_RECONCILE and FIN_CORR_DISPLAY in ECC, as mentioned in notes 2896400 & 2887318 ?



        • Hello Kapil,

          I understand your point related to the SI checks. I will keep in mind this feedback.

          You can execute FIN_AA_CORR_RECON & FIN_AA_CORR_DISPLAY, FIN_CORR_RECONCILE and FIN_CORR_DISPLAY at any point in time in the source system- they indicate data related consistency errors. So they are not directly connected to the SI checks.


          Kind regards,


    • Hi Sorina

      We are facing issue while executing FIN_CORR_MONITOR tcode in ECC system. When we execute this report in Correction mode to rectify table inconsistencies, system starts background job which gets automatically terminated with error message "Define a leading ledger" FAGL_LEDGER_CUST023.

      • We are on classic G/L, and in SPRO there is no option to define ledger. How should I resolve issue ? We dont have business requirement for Parallel ledger.
      • Even if Leading leddger is defined in ECC, Will it create any issue later ?