Hi there, Mak Mashal.
Welcome to the QuickBooks Community. I can share details to ensure you're able to fix the reconciliation discrepancies.
When you open the Reconciliation window and choose an account to reconcile, the Beginning Balance is zero or incorrect. This may be due to one of the following reasons:
I suggest reviewing your previous period's reconciliation to determine which of the above-mentioned is causing the error. This will help us determine whether the opening balance for the current period is correct. You can follow the steps in this link: Fix beginning balance issues if you've reconciled the account in the past QuickBooks Online.
Please refer to this article to view various information or guidelines you need to help to fix any reconciliation issues and how it works: Learn the reconcile workflow in QuickBooks.
Let me know how it goes in the comments below. If you have other banking concerns or inquiries about reconciling your accounts in QuickBooks. I'm just around to help. Take care always.
Thanks for posting in the Community, Mak,
If there's a change made on a previous reconciliation period, you'll have to undo the reconciliation to zero out the discrepancy. We'd recommend to run a reconciliation report. Here's how:
You'll see any changes made from a previous reconciliation period. Then, to undo a reconciliation you need to do it per transaction in the Account history. Here's how:
You may want to check these article about bank reconciliation in QuickBooks Online:
If you're not sure where the discrepancy came from, we'd recommend checking them with your accountant or bookkeeper to get more information to avoid messing up your books.
Drop a comment below if you need more help in QuickBooks Online. Have a nice day!