Why when I enterred the opening balance of a customer and run the trial balance report, it reflect the opening balance in sales as credit balance!. what is the problem?

Let me help you fix this, @snfcompany2020.

I've replicated this one to check if there's an ongoing issue with the program. However, the opening balance was reflecting under the debit column.

I recommend deleting the opening balance for this customer then add it back so we can record it correctly. Here's how: 

1. Go to the Reports menu and open the Trial Balance report.
2. Click the amount to open the opening balance of the customer.
3. Select the invoice to open it. 
4. Once opened, click More and select Delete.
5. Click Yes.

Once done, go back to Customers section and edit the same to add the opening balance. Just follow these steps:

1. Go to Sales and select Customers.
2. Click the name of the customer, then select Edit.
3. In the Payment and billing section, enter again the opening balance and click Save.

Then, you now run the Trial Balance report to check if the opening balance was posted in the Debit column. Just go back to the Reports menu and open the Trial Balance report.

If you're still getting the same result, it could be there's an issue with the browser. Let's fix this by following these recommended steps:

First, let's use a private window to access your account. This a special mode where the browser doesn't record the browsing activity on the local device, so no trace will be left on the computer. Here's how:

• Press Ctrl + Shift + N (Google Chrome).
• Ctrl + Shift + P (Firefox or Internet Explorer).
• Control + Option + P (Safari).

 
If it works, then let's clear the cache in your web browser or try using a different supported browser. This might be a temporary issue with QuickBooks and the current browser that you use.

Let me also provide you a link to check if your browser is compatible with QuickBooks: Fixit.intuit.com.

The Community always has your back, so please let me know if you have any questions.

Thanks Raymond,

That's exactly the solution of the issue. I entered the opening balance date as 31/12/2019 not 1/1/2020. I just tried it and get it solved and the opening balance of sales account is nil.

Much appreciate it dear.

That exactly the solution of the issue. I just changed the opening balance date from 1/1/2020 to 31/12/2019 and get the opening balance correct with no impact to the sales account.

Much appreciate it dear!

With respect to your clarification below:

But for the proper accounting data is to enter open invoices again in QuickBooks and ignore the entering opening balance field in the Customer Information page.

For example:

• if you have an open invoice dated 11/11/2019, enter it again, the same way in QBO.
• if you have an open invoice dated 02/11/2020, enter it again, the same way in QBO.

I do understood that I should entered the transactions in the customer information page the same dates you mentioned above. My question here that do that will affect the sales account or not for the year 2020? 

Also, I have a question:

For example:

• if you have an open invoice dated 11/11/2019, enter it again, the same way in QBO.
• if you have an open invoice dated 02/11/2020, enter it again, the same way in QBO.

How will I record these transactions? If I record them as sales transactions, they will be reflected in the sales account as sales transactions !!

@snfcompany2020 

Create Invoices again in QBO - same original date, same product/service item.

Let QBO handle it after that. This way you also have updated Accounts Receivable (Aging) in QBO. When you receive payment, you can also apply for the payment against the right Invoice. Hope this helps!