I took over accounting from someone who clearly did not know what they were doing.  I have compared the G/L bank account with the bank statements, and having gone back 3 months now, the bank account closing balance in Sage is out by a large amount each month.  What is the easiest way to determine where the error occurred and how can I fix it, if the bank account was reconciled say in February with an error and that error was carried forward to the end of the year?