I have an old personal QB account that was never reconciled (going back to 2014, they are in the reconcile box but no access to the old statements). Can I adjust the beginning balance to be able to start fresh, reconciling from January 1, 2019?
We're unable to adjust the Beginning Balance of a reconciliation.
You can reconcile your transactions from 2014 to 2018. You can do it yearly. Just be sure that the ending balance in 2018 is correct because that will be your beginning balance in the January 2019 reconciliation.
Please consult an accountant if you get a difference, so they can suggest an adjustment for your transactions in 2018 or earlier.
Feel free to reach out if you have other questions about reconciliation.