When you highlight a specific bank account, then click Reconcile, the message below appears:

The bank account selected has been marked as not requiring bank reconciliation

This is because No Bank Reconciliation has been selected in the Bank record. To resolve this you need to disable this setting in your bank record. Let's do this now.

1. Select the bank account you are trying to reconcile.
2. Click Edit, or double click the bank account.
   
   The bank record opens on the Accounts Details tab.
   
   
3. On the right where it says Bank Reconciliation, deselect No Bank Reconciliation.
   
   TIP: No Bank Reconciliation is greyed out and unable to be changed? - Read more >
   
   
4. Click Save.

Now you can reconcile this bank account.