I downloaded the bank transaction but old one is gone

Hi there, @jounrals not published. I've got here steps to help you find the missing transactions in QuickBooks Online (QBO). 

To start, may I know the specific name of the bank you're having problems with? This is helpful so I can check here on our end if there are any maintenance issues between the bank and the program.

In the meantime, we can review your account's history to find those missing old transactions. Here's how:

1. Navigate to the Bookkeeping and select Chart of Accounts.
2. Next, find the bank account and click Account History.
3. Then, look for the transaction and click it to get more details.

If you can't see them there, the transactions right have not been categorised into specific accounts, the program might put them into the Uncategorised Income or Uncategorised Expense account. To verify, we can check these accounts:

1. Go to Bookkeeping and select Chart of Accounts.
2. Look for the Uncategorised Income or Uncategorised Expense accounts.
3. Next, select Run Report.
4. From there, look for your missing transaction on the report.

However, if you're still unable to find those old transactions, we can review the tabs on your Banking page. I'll guide you on how:

1. Select the Bookkeeping menu and click Transactions then select Bank Transactions.
2. From there, click the tile for the bank account you downloaded the transaction from.
3. Next, let's check the For Review tab. Set the correct date range and look for the missing transactions. If you find them, you can now categorize them into the correct account. 
4. If you're unable to see it there, we can now go to the Categorised tab. Filter the date again and locate those transactions. If you find them, but it's in the wrong account, refer to these steps to unmatch and move them.
5. If you're still unable to see those old transactions let's now check the Excluded tab. If you verified that the transactions are there, just click the Undo button to get them back into the For Review tab.

For reference, check out this article: What to do if you can’t find downloaded transactions in QuickBooks Online.

It's also recommended to regularly perform the reconciliation process to ensure your account's balance matches your real-life bank statement. 

I'm just around the corner to lend a hand if you have any other concerns locating your bank transactions in QBO. Have a good one.