If opening balance is incorrect aacording to previous year's balance,follow these steps to correct it
Step 1 Take backup before runnning any process
Step 2 Then open your company and then switch to previous financial year
Step 3 Now in last year,check out the bank ledger and all entries,and add corrected entries
Step 4 You can also update master balance option after backup in last year
Step 5 Now go to adminstration and then select change financial year option
Step 6 Now change to next finacial with new and changed option and proceed to change
Step 7 Now you can check your opening balance of bank ledger,it will be updated according to closing of previous financial year
Note:If incase if it is single financial year company,then you can change opening manually