The year end tool moves your balances to more relevant nominal codes:
When you run the tool we put a lock in place on the account to prevent previous transactions from being modified. There are a few ways to tell if this has been run:
Go to Account Settings >> All Settings >> Account Lock Date. This will be updated to show the lock date of the year end procedure
Go to Account Settings >> All Settings >> Simplified Year End Tool. This will show you the available years. If 2017 isn’t showing, it’s likely to have been run.
Go to Reports >> Journals. When the tool is run, it creates a journal. This is named as “Year end journal - dd/mm/yyyy”
You can to an extent, but it’s common for some movements to made by your accountant before the year end is run.