How-to Guide
Opening Balance Lock (and Why It Matters)
Opening balance lock creates a trusted ledger boundary after migration so your history stays stable and your month-end close stays predictable.
What is an opening balance lock?
An opening balance is the starting point for your books in Prosper. Locking it means you're confirming: “These balances are correct as of the cut-off date, and historical imported data should not change.”
This creates a stable boundary: keep your prior system as historical reference, and let all new activity flow through Prosper.
Step 1
Choose a cut-off date
Pick a date that becomes the boundary between your old system and Prosper (e.g., start of a month or quarter).
Step 2
Import historical data
Import transactions up to the cut-off date via CSV or migration flow. Make sure account mapping is correct.
Step 3
Verify balances
Compare Prosper's opening balance report to your prior system closing balances as of the cut-off date.
Step 4
Lock the opening balance
Once verified, lock the opening balance to protect historical data and create a trusted ledger boundary.
Why it increases trust
- Protects historical data from accidental edits
- Makes reconciliation and month-end close repeatable
- Creates a clear story for your CPA during review
- Reduces “import drift” when changing systems
What to do before locking
- Confirm account mapping is correct
- Check for duplicate or missing transactions
- Reconcile accounts to your statements
- Compare key balances to your prior system as of the cut-off date
Follow our reconciliation guide.
After locking
After you lock the opening balance, treat the prior system as read-only history. If you discover an issue, you'll need to correct it forward (not by editing history) so the ledger remains trustworthy.
Next: audit-ready bookkeeping and accountant pack export.
Ready to migrate safely?
Start free and use a clean cut-off workflow built for correctness.
Migration guides: QuickBooks · Xero · Pricing