Setting Opening Balances for Business Partners 
During System Initialization, the opening balances for Business Partner Accounts must be updated with legacy data.
Since the opening balance usually includes several invoices, specify the payment amount as a partial payment of this position. Note that opening balances are not included in the dunning.
The opening balance in the system currency is determined automatically by the system on the basis of the national currency.
If the master records of the Business Partners are entered in the system with a foreign currency, the opening balance can also be specified in this foreign currency. The OB (FC) column is only ever active in this instance.
Enter the value without a plus sign if the balance is in credit. If the balance is in debit, insert a minus sign in front of the value. Note that this setting is also dependent upon the option chosen in Display Credit Balance with Negative Sign in 
Administration 
System Initialization Company Details 
.
If the opening balance is specified in the foreign currency, the system calculates the opening balance in the national currency on the basis of the exchange rate that applies on the reference date, and displays this in the OB (LC) column. This value can be altered manually.
Procedure
From the SAP Business One Main Menu, choose
Administration System Initialization Opening Balances Business Partners Opening Balance
.The Business Partners Opening Balance – Selection Criteria window appears.
Set the required business partner range, and choose OK. The Business Partners Opening Balance window appears.
Specify the offsetting account for the business partner opening balance postings, and enter all the other required details in the window header.
Enter opening balances in the local currency in column OB (LC) only if data is to be entered in the local currency.
If the system currency is different from the local currency, the system automatically calculates the opening balances in the system currency and displays the values in column OB (SC).
Enter the opening balance in the foreign currency, if required.
If a foreign currency has been defined for a business partner, the OB (FC) field is active. SAP Business One automatically calculates the amounts in the local and system currencies, using the valid exchange rate on the value date. Overwrite the calculated values if necessary.
Choose Add to create the opening balance transactions.
Result
SAP Business One creates the opening balance transactions for the business partners updated in the Business Partners Opening Balances window. The original type assigned to these transactions is OB.