When you import cash receipt transactions using Lockbox Processing in Microsoft Dynamics GP, only the first check is imported in where this check number is duplicated in the import file. It will skip the succeeding records for the duplicate check number and these transactions are not listed on the exception report, so the user does not receive any messages that indicate that the transactions were not imported.
This problem occurs because duplicate check numbers exist in the imported transactions.
To work around this problem, you must add another field to the Lockbox import file to make the record unique, such as Customer ID or Customer Name. To do this, follow these steps:
Open the lockbox file by clicking on Cards, point to Sales and click on Lockbox .
Bring up the Lockbox ID you are using.
In the lockbox mapping, add Customer Name or Customer ID to the Header row.
Ask the bank to include either the Customer ID or the Customer Name to the lockbox file they generate. Make sure you mapped the field in the Lockbox file to the same spaces in the line that the bank added it to the lockbox file.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.