Item missing from bank account

Hi there all,

So I'm reconciling our bank account and it keeps coming up with, we'll say out by $100.

It says that there is a $100 deposit that I have not ticked off, however I have been through my bank statements twice and manually ticked off everything and it still appears as $100 out.

Can anyone help me?  I need to know where to look to try and find the error.

Thanks in advance

Tania