How do I lock periods to prevent backdated edits from unreconciling matches?

Lock the accounting period from the Period Close Checklist once reconciliations are complete, restricting new AP, AR, and payroll postings to that period. Only users with an explicit override permission can then post backdated transactions, which keeps an already-reconciled period from silently drifting out of balance.

By Zuny Fester, Head of Operations and Marketing

Reviewed by Zuny Fester

Published September 10, 2026Last reviewed September 10, 2026Editorial policy

Part of the month-end close guide.

Where to lock	Lock Accounting Period page, from the Period Close Checklist
What locking restricts	New A/P, A/R, or payroll postings to that period
Who can still post	Users with the Override Period Restrictions permission
What it doesn't do	It doesn't retroactively fix an error already in the period — that requires unlocking

Locking versus closing

Locking restricts new postings to specific ledgers (A/P, A/R, payroll) to preserve the integrity of balances that have already been reconciled, while fully closing a period disables all new postings entirely. Most teams lock A/P, A/R, and payroll individually as each subledger's reconciliation completes, then fully close the period once every reconciliation and review is done.

Why this specifically protects reconciliation

A reconciliation confirms two numbers agree as of the moment it's performed. If someone can still backdate a transaction into that period afterward, the reconciliation's conclusion is no longer reliable — the numbers it confirmed have silently changed. Locking closes that gap: anyone without override permission simply can't post into a period that's already been reconciled and locked.

Next step

Map the finance workflow with the most exposure and prove the automation path.

Bring the invoice, contract, payment reconciliation, or customer finance workflow you have to defend at audit. Loopfour can map the trigger, controls, integrations, and approval loop.

Book a workflow review

Checklist

Setting up period locking correctly

Lock A/P, A/R, and payroll individually as each subledger's reconciliation completes
Restrict the Override Period Restrictions permission to a small, named group
Consider enabling a minimum unlocked-period window to prevent premature future-period posting
Fully close the period once every reconciliation and review is finished

Frequently Asked Questions

Only by a user with the Override Period Restrictions permission, and any such edit should be documented and reviewed, since it bypasses the protection locking is meant to provide.

A completed reconciliation can silently become inaccurate if a backdated transaction posts afterward, without anyone necessarily noticing until the next reconciliation reveals a discrepancy.

Many teams enable a rule that keeps only a set number of future periods open for posting, preventing transactions from being entered too far ahead of when they should be.

Sources

Topic

Month-End Close

Month-end close is the set of accounting tasks a company runs after a calendar month ends to turn raw transactions into a finished, trustworthy set of financial statements: reconciling subledgers, boo…

Diagnostic

What causes a bank reconciliation to not balance?

In order of likelihood: a transaction was entered twice or not at all, an amount was transposed or mistyped, a bank fee or interest payment was never booked, a deposit in transit or outstanding check wasn't accounted for, or the beginning balance itself was wrong because a prior period's reconciliation was never actually correct.

How-to

What should be on a month-end close checklist?

A complete close checklist covers subledger lockout, bank and balance-sheet reconciliations, accrual entries, intercompany revaluation and elimination if applicable, inventory review if applicable, consolidated review, and period lock. Each task should have a clear owner and a place in the dependency order, not just a due date.