Please bear in mind that the Current Balance on your cashbook screen should match the nominal balance of the bank account as at the furthest forward point in your accounts (this is usually N12 / N13).
To check this:
Select Financials, Cash Book (ribbon menu) or Cash Book, Cash Book Overview (Classic/Module menu)
Click the magnifying glass icon and select the correct bank account.
Make a note of the Current Balance figure.
Select Financials, Accounts (ribbon menu) or Nominal Ledger, Records, Accounts (classic/module menu)
Find the relevant nominal account using the lookup / search.
Select the blue arrow next to the period to date figure.
Check the balance figures for period 13 next year - this should match the cashbook balance figure you noted in step 3.
If these do not match then further investigation will be required, so please raise a new case online and reference the title of this article and include the cashbook figures and the nominal balances.
It will also be necessary to carry out the investigation on a copy of the database. If your database is not hosted by Access, please include details of how to obtain a copy of it.