Am trying to reconcile old accounts in order to file back tax reports, going back to 2015. How do I do this?

Hi there, jak3.

When you reconcile past accounts, it will affect the current banking balances. To avoid this, I suggest undoing first all the reconciled transactions. Then, start reconciling again from old accounts. Take note that you have to undo each transaction manually.

However, if you have too many transactions to undo and you're connected to an accountant in QuickBooks Online, you can ask your accountant to undo the reconciliation for you.

Follow the steps below on how to manually clear, unclear, reconcile, or unreconciled individual transactions in QBO:

1. Click the Gear icon at the upper right corner.
2. Choose Chart of Accounts.
3. Locate the appropriate account for the transaction.
4. From the Action column, select View Register (or Account History).
5. Identify the transaction to edit.
6. In the reconcile status column (indicated by a checkmark), select the box and keep clicking it until the box is blank. This removes the transaction from the reconciliation.
7. Hit the Save button.

For additional information, you can refer to this article: Undo and remove transactions from reconciliations in QuickBooks Online.

Once done, you can start reconciling the past transactions. You can check this article to see the detailed steps and information: Reconcile an account in QuickBooks Online.

If your QuickBooks account doesn't match your bank statement at the end of reconciliation, please check this article: Fix issues when you're reconciling accounts in QuickBooks Online. This contains steps on how to fix the difference.

Please let me know if you have other concerns in reconciling your accounts in QuickBooks. I'm always here to help.