Period Lock
A period lock is a "locked through" date set on a book, enforced by the database, that refuses any posting on or before it and can only ever be moved forward, never backward.
In short
The mechanism behind closing the books. Set a lock through June 30th, and no categorization, manual entry, or reversal dated on or before that date can post — not even one that tries to bypass the application. The lock can move to July 31st later, but never back to June 15th.
Also called: locked period, locking a period
A period lock is a single "locked through" date recorded on a book. Once set, no entry — no categorization, no manual journal entry, no reversal — can post on or before that date. This is enforced by the database itself, not merely by the application's interface, so it holds even against a write that tries to bypass the app entirely.
The lock moves in one direction only: forward. It's possible to extend a lock from May 31st to June 30th later, but never to move it back to May 15th — a closed period is meant to stay closed, permanently, not get reopened because it would be convenient for one transaction. A lock that could be casually reversed wouldn't actually protect anything.
Locking pairs naturally with reconciliation: reconcile first, confirm the ledger matches the statement, then lock through that date. Locking before reconciling just means discovering a discrepancy later that can no longer be fixed in place, since anything dated in the now-locked range is refused.
Like every other tool that writes to the ledger, setting a lock previews first — showing the current lock, if any, and what it would become — and only actually applies once confirmed. Trying to post anything dated on or before an existing lock is rejected outright, with a clear reason pointing to the lock date, rather than silently allowed through.
What people get wrong
- Trying to move a lock backward to reopen a period — it's refused by design; the lock can only ever extend forward.
- Locking a period before reconciling it — that just means finding a problem later that can't be fixed in place anymore.
- Assuming a locked period blocks reports as well as postings — locking only stops new entries from posting; every report can still be pulled for a locked date range.
Common questions
- Can I unlock a period if I need to fix something in it?
- Not directly — a lock can only move forward, never backward. The fix is a reversing entry dated after the lock, not reopening the past.
- What happens if something tries to post before the lock date?
- It's rejected outright, with a clear reason pointing to the lock — nothing silently slips through into a closed period.
Machine-readable: /api/knowledge/concept:period-lock