In order for the system to check the duplicate Customers in SAP, please maintain an entry for message no F2 145 in SPRO –> Financial Accounting –> Customer Accounts –> Master Data –> Preparation for creating Customer Master Data –> Change Message control for Customer Master data.
This node also can be reached via SPRO –> Logistics – General –> Business Partner –> Customers –> Control –> Change Message Control for Customer Master Data
This message gets switched on if the system finds an entry here. Maintain the value as I for online (for a Note in a Window. i.e. for an Information message) and “-” for switching off this message. You can control this message for Online as well as Batch input. SAP standard is just an Information message which gets kicked in if Customer’s or Business Partner’s Nam1 or Name2 and Search term exactly matches to any of the existing customer or Business Partner.
If you want to make this message an error message, please execute OBMSG transaction and change the settings for F2 application area to include the options of Error and Warning, etc. and also change the default behaviour. Please note that this change is in the SAP’s Entry Area and SAP recommends not to make any changes. However, if it is unavoidable, you can make this change and cdocument it properly. This change will be overwritten in the next upgrade of your system.
The fields which the system checks are: name1, name2 and Search term1. They should exactly match for this check to be switched on for a new customer and it shows the existing customer with the excat match.
For IS Media, Duplicate Check Active indicator needs to be set for performing check of duplicates. This indicator can be set at SPRO — > SAP Media –> General Settings –> Maintain General IS-M Control Parameters.
However, duplicate check is not supported when BP is created via IDOC or BAPI