What to do when a closed period changes in Xero

Written by an ACA-qualified finance manager · about the author · Last reviewed 1 July 2026

You locked the month, signed it off, sent the pack - and now Xero doesn’t match what you reported. Here’s why, how to spot it, and what to do.

Why a “closed” period can still change

Locking a period in Xero sets a lock date: but it’s a soft control, not a vault. A few things still move a closed month: an admin lifts the lock to fix something and forgets to put it back; a bill or invoice is entered dated in the closed period; a correcting journal is backdated; or an integration (a payments app, an e-commerce sync) posts historic transactions. And because Xero’s balance sheet is cumulative, a single backdated entry shifts the as-at balances of every period from that date forward - including ones you’d already signed off.

How to tell something has changed

• Compare to your sign-off. The reliable way: keep a snapshot of the balances you signed off and compare them to Xero today. Any difference is a post-close change.
• Check the lock date. If it’s been moved or removed, treat the period as open until proven otherwise.
• Run a journal or transaction report filtered to the closed period’s dates and sorted by entry/edit date - anything entered after sign-off stands out.
• Use Xero’s history. Most records carry a history of edits and who made them.

What to do when you find one

1. Understand it. What moved, by how much, and why - a genuine late item, a correction, or an error?
2. Decide if it’s material. A few pounds you note and move on; a material change needs action.
3. Fix at source if you still can. If the pack hasn’t been issued, the cleanest fix is to restore the closed month - reverse or re-date the entry so the period agrees with your sign-off again.
4. If the pack is already out, don’t quietly rewrite history. Reverse the item out of the closed period and re-post it in the current open month, so the reported numbers stand and the correction is visible and dated.
5. Document it. Record what changed and how you handled it - an adjustment register. That’s what makes the change defensible to an auditor or the board.
6. Tell whoever relied on the number. If it went in a board pack or a filed set, the people who used it need to know it moved.

How to stop it happening

Set and keep lock dates; limit who can edit closed periods with Xero’s user roles; and, the only way to be sure, monitor closed periods for change rather than hoping nobody touched them. That last point is the whole reason Postlock exists: it snapshots every balance at sign-off and tells you, within hours, when something lands in a period you’d already closed, naming the document, who posted it and when.

Frequently asked questions

Does locking a period in Xero stop all changes?

No. It’s a soft lock - it can be lifted, and entries can still be backdated into a closed period. It deters accidents; it doesn’t guarantee the numbers are frozen.

How do I know if someone changed a closed month?

Compare the balances you signed off to Xero now, check whether the lock date moved, and run a transaction report for the period sorted by entry date. The reliable way is to snapshot your sign-off and diff against it.

Should I reopen the period to fix a change?

If the pack hasn’t been issued, yes - restore the closed month so it agrees with sign-off. If it’s already out, don’t rewrite history: reverse the item and re-post it in the current open month, and document it.