SAP S/4HANA Business Partner Conversion: How to Handle Legacy Customer/Vendor Links in BD001 and BC001

This article explains how to identify legacy mappings, analyze inconsistencies, migrate the links, and ensure the system meets S/4HANA readiness checks. Experts at TeamIdea support and accompany you with this straightforward and easy-to-follow visual guidance material. It will lead you through every stage of the SAP S/4HANA Business Partner Conversion, ensuring each step is completed correctly and consistently.

The Essentials of the Conversion

Before moving an SAP ECC system to SAP S/4HANA, every Customer, Vendor, and Contact Person must be transformed into a Business Partner (BP). This prerequisite step — Customer-Vendor Integration (CVI) Conversion — is often challenging when historical Customer/Vendor relationships are still stored in legacy tables BD001 and BC001. These tables were used in early ECC releases to map a Customer or Vendor to a Business Partner. Beginning with ECC 6.0, SAP introduced a redesigned CVI framework with new link tables (CVI_CUST_LINK and CVI_VEND_LINK). However, old mappings are not automatically transferred to the new structure. This mismatch leads to CVI inconsistencies and, ultimately, prevents the system from being converted to S/4HANA.

Background: Why BD001 and BC001 Still Matter

In ECC 5.0 and below, Customer–BP assignments were stored in BD001, and Vendor–BP assignments in BC001. From ECC 6.0 onward, SAP delivered a redesigned CVI model with: CVI_CUST_LINK, CVI_VEND_LINK
Old relationships remain in BD001/BC001, while new Customers/Vendors are written only to the new CVI tables. SAP intentionally did not migrate old entries due to design decisions at the time. SAP S/4HANA conversion tools (especially SUM) validate only CVI_CUST_LINK and CVI_VEND_LINK and ignore BD001/BC001.
This creates a situation where: the business partner technically exists, legacy links exist in BD001/BC001, but the new tables appear empty, causing SUM to block the migration.

Typical Scenario

However:

CVI_COMPL_CHK lists the Customer as not fully converted. Although an assigned Business Partner exists:


CVI_LINKS shows a BP relationship, but with a remark: “Mapping stored in BD001.” CVI_CUST_LINK has no entry. To proceed with S/4HANA, these historical links must be migrated.

Overall Conversion Approach

To avoid this, the process consists of two main phases:

Phase 1: Consistency Checks
Identify and remove incorrect or obsolete BD001/BC001 entries. To accomplish this, please To find and follow instructions of SAP note:

 1105558 - BP_CVI: Migration report from Note 851445 terminates.

 Typical inconsistencies include:

• Missing BPs for existing Customers/Vendors
• Missing Customers/Vendors for existing BP links
• Multiple BPs assigned to a single Customer or Vendor

These issues must be corrected manually in SE16/SE16N before proceeding.


Phase 2: Migration Steps
Convert legacy table entries to the new CVI link tables and synchronize tax data.


Both phases use SAP-delivered reports that must be executed in a strict sequence.

Below is the required sequence of reports, along the mind map


Step 1 — Analyze Customer Tax Numbers

CVI_ANALYZE_CUST_TAX_NUMBERS

• Checks mismatches between Customer tax data and BP tax data.
• Must be executed before any synchronization or link migration.
• View results in SLGD application log.

Step 2 — Analyze Vendor Tax Numbers

CVI_ANALYZE_VEND_TAX_NUMBERS

Performs the same analysis for Vendors.

Step 3 — Synchronize Customer Tax Numbers

CVI_SYNC_CUST_TAX_NUMBERS

• Aligns tax data between Customer and BP.
• Direction can be chosen depending on which object is considered leading.
• “Automatically switch direction” option ensures that the object without tax details is updated.

Step 4 — Synchronize Vendor Tax Numbers

CVI_SYNC_VEND_TAX_NUMBERS

Identical approach as for Customers.


Step 5 — Migrate Customer Links from BD001

CVI_MIGRATE_CUST_LINKS

• Transfers BD001 entries → CVI_CUST_LINK
• BD001 can be cleared afterward
• Must be executed only after completing tax data analysis and synchronization.

Example result: Customer AM007 → BP AM007 entry now appears in CVI_CUST_LINK.


Step 6 — (Optional) Migrate Vendor Links from BC001

CVI_MIGRATE_VEND_LINKS
BC001 → CVI_VEND_LINK migration.

Optional because the system continues reading BC001 for fallback, but recommended for performance and S/4HANA readiness.


Step 7 — Adjust Role Customizing

CVI_ADJUST_ROLE_CUSTOMIZING


This report:

• Moves old BP role applications (FLCU, FICU, LOCU) to the new CVIC application
• Updates datasets
• Maps field groups to their new equivalents
• Optionally deletes obsolete configuration.

We recommend:

Running the report without deletion first (test mode) and executing it again with deletion once transport routes are confirmed

Validation and Cleanup

• Conversion Completeness. 
  

Run CVI_COMPL_CHK — Customer should no longer appear as “not converted.”

• Link Verification
  

Run CVI_LINKS — mapping should now reference CVI_CUST_LINK.

• Cleanup
  

Legacy entries in BD001 and BC001 can now be deleted via SE16N.

Conclusion

Migrating historical Customer/Vendor–BP mappings is a mandatory part of preparing ECC for S/4HANA. Legacy BD001 and BC001 entries must be:

• Analyzed
• Cleaned
• Synchronized
• Migrated

Once moved into CVI_CUST_LINK and CVI_VEND_LINK, the system passes SUM validation and is ready for S/4HANA conversion.



Please, refer to more SAP notes and do not hesitate to ask your TeamIdea colleagues:

2601760 - What's the difference for the entries in BD001/BC001 and CVI_CUST_LINK/CVI_VEND_LINK?

851445 - BP_CVI: Details about reports to be executed for ERP 2005