There could be several reasons for a mismatch in the closing of the last year and the opening in the current year. You can follow these steps to check this:
Step 1: Take a backup of your data. Then open the last year and in the Housekeeping Menu, check for junk characters and incomplete vouchers. If found, clear them.
Step 2: Run the Update Master Balance process.
Step 3: Go to Administration, change the financial year, and then click on your current year.
Step 4: Click Yes to carry forward the balances. If the data size is small, click on All Masters. If the data size is big, click New and change masters.
Step 5: Check the balance of your masters.