In System>>Settings there is a setting called "Locking". Here you can specify dates for the various transaction registers. It will not be possible to post transactions earlier than the Dates you set here.
This setting also contains a check box named "Disallow creating new records with trans. dates later than current date". Ticking this option allows you to block transactions from being posted in the future.
Note that locking can only be undone (moved to an earlier date) by someone who has the correct Access setting in System>>Settings>>Access Groups.
HansaWorld Support Team