Customer and Vendor Master Data: Duplicate Check
Description
For Release 3.0A, when creating a new account or when changing an address, the system checks whether accounts with the same address have already been created. Any duplicates that are determined are displayed in a window. If you select CONTINUE the action you have just selected is continued; selecting CANCEL returns you to the address screen.
Change system parameters in customizing
For run-time reasons, the default setting for the duplicate check is "off". You can switch it on via the Financial Accounting Implementation Guide. The message group is "F2", and the message number for vendors is "144" and for customers "145".
For further information, refer to the Accounts Receivable and Accounts
Payable" Implementation Guide in the chapters 
"Change message Change message control for customer master data"
and
"Change message control for vendor master data" .
The matchcode fields are used for the search. This means that use of
upper/lower case does not affect the search for duplicates. To find out which
field contents are behind the matchcode fields, refer to the Financial
Accounting Implentation Guide. Read chapters
"Check search fields for (customer) matchcodes" and
"Check search fields for (vendor) matchcodes".
Effect on batch input
If you switched on the check for batch input and choose the option "Extended log" when processing the batch input session, you receive an information message in the log for any duplicates found. This does not, however, prevent the account from being either created or changed.