Help / Accounting and reports

Lock financial periods

Stop new postings in a closed month by locking its accounting period.

A financial year is split into accounting periods, normally one per month. Locking a period stops anything dated inside it from being posted, so a month you have finished reporting on cannot change by accident. Open Accounts > Accounting > Financial Years & Periods or go to Financial Years & Periods. You need access to the Accounting module; locking and unlocking need edit access.

Set up the year

A company with no financial year sees "No financial year yet". Click Set up accounting (it needs create access). This creates the current financial year, starting in the month and day set in the company's settings, with one period for each of its twelve months, for example "January 2026". It also adds any standard account that is missing, and is safe to run again. The year is named like "FY 2026-27".

Lock a period

1. Find the period in its year. Each row shows the Period, From, To and its State: Open or Locked.
2. Click Lock on the row.
3. Read the confirmation, "Lock <period>?", and click Lock period.

The state changes to Locked and a message such as "<period>: Period locked." appears.

What a lock does

• Nothing dated within the period can be posted: manual journal entries, and the entries made by invoices, bills, payments, expenses, POS sales and reconciliation adjustments. They are refused with "The accounting period covering YYYY-MM-DD is locked. Cannot post to it."
• An existing entry in the period cannot be voided either, so voiding an invoice, bill, payment or expense dated in the period is refused with the same message.
• Entries already posted are not changed, and the period's reports still work.

Unlock a period

Click Unlock on the row and confirm Unlock period. You can lock and unlock as often as you like. If someone has already changed it, you see "Period was already locked." or "Period was already unlocked." and nothing flips back.

Good to know

• A date that falls outside every period of every financial year is not restricted by locks. Check that your year covers the dates you work with.
• There is no year-end closing step in Legasum. Profit is not moved into Retained Earnings; the Balance Sheet shows it as Current Earnings (unclosed) instead.
• A year can show a Closed badge, but there is no button to close one.
• Locking is the right way to protect a month after you have filed a return from it. See Tax Summary.
• Locks apply to the whole company, not a single branch.