Sage 50 automatically blocks transactions that are dated before the start date of the previous financial year. If you see the option as grayed out and you are not allowed to select a date or getting Sage Invalid Date Error , please make sure you are in single user mode and all the other screens are closed. Now, follow the steps given below-
You can also stop transaction prior to a specified date from being posted by using the Lock Date feature. If anyone tries to post a transaction prior to this date, he will receive an error message. However, if you are logged in as manager or you have the lock date access, you can override the warning and post such transactions.
Here is how to set a Lock date–
You can also configure the Lock Date access rights of any user, to prevent accidental posting-