Hello there, Setsun.

It's good to know that you've already checked and reviewed the register. I appreciate you for doing that.

Since there's no opening balance entry, you'll have to use your bank statements to make sure the opening balance is correct. Then, take note of the date and amount of the oldest transaction in the account. Once done, you'll need to create a journal entry for this. 

1. Go to the +New button.
2. Select Journal entry under Other.
3. Enter a date that comes before the oldest transaction in the account. This will be the opening balance date.
4. On the first line from the Account drop-down menu, select the account you want to enter the opening balance for.
5. We recommend adding a note in the Description field so you know what the journal entry is for.
6. On the second line from the Account drop-down menu, select Opening Balance Equity.
7. Use your bank statements to enter the opening balance. Note: Enter the balance of your real-life account for the date you picked as the opening balance.
8. Enter the debits and credits based on the type of account you entered on the first line.
   

Afterward, go back to the Chart of Accounts tab to reconcile the journal entry. This prevents it from showing up on your future reconciliation. Here's how:

1. Go to Accounting on the left panel.
2. Within the Chart of Accounts, find the account and select View register from the Action column.
3. Search for the journal entry you just created.
4. Select the box in the checkmark column until you see an R. This reconciles the journal entry.
   

Also,  I'd recommend reaching out to your accountant for further advice on fixing the beginning balance issue in QBO, especially when creating a journal entry.
 

For additional details and tips, feel free to check out these resources:

• Reconcile an account in QuickBooks Online.
• Learn how to review your beginning balance and look for issues for accounts you haven't reconciled b....

If you still need help with the process, please let me know by commenting below. Always take care and have a great day!