How is it even possible that this program allows duplicate invoice numbers?

Hello, @dave_thompson.

Currently, there isn't an option in place to warn if a duplicate customer invoice number is used in QuickBooks Self-Employed if you manually enter them. The invoices in QuickBooks Self-Employed are for tracking purposes only and they don't affect your business and tax reports. 

For now, you can manually track the invoice transactions and edit the invoice number. To do so, please refer to these steps:

1. Go to the Invoices menu.
2. Look for the Invoice you need to edit, click it and select Edit Invoice.
3. In the Invoice no. box enter the correct invoice number.
4. Click Save as draft or Send invoice.

I’m also adding an article that provides an overview of the Invoice feature. It includes instructions on how to customize the sales template, turn on the payments option, etc.: Create invoices in QuickBooks Self-Employed.

Also, when you receive the invoice payments, make sure to track them under the Transactions page. You can use this link for more information: Manually add transactions in QuickBooks Self-Employed.

In case you need to set your numbering preference, you can use the  Custom transaction numbers feature in QuickBooks Online. This adds an Invoice no. field where you can enter any number or letter format you want and the sequence you set here applies to all sales forms: How to change the invoice number on sales forms.

If you have further questions about invoices in QBSE, please leave a reply below. I'll be always around to help. More power to your business. 

This doesn't address the question.  Of course the duplicate invoices impact my business.  If a duplicate isn't paid, and I've lost all tracking of a duplicate invoice because it is a duplicate, then I've lost that money and it DOES impact my revenue and taxes!  I even have an invoice that was triplicated.  This company needs to figure out how to eliminate duplicate/triplicate invoices.  If it's pilot error I need to know what I'm doing to cause it.  Not only does it have a monetary impact it has a perception impact by those customers I have to go back to and say, I can't track your invoice - I lose credibility because of this program.  I am researching others.  I don't need other b.s. articles to read.  I need quickbooks to fix the issue - quickly.  In addition, if I'm using the poorly designed "reports" I can't accurately track revenue by customer.  I do not manually enter an invoice number - ever.

Having same issue. QBs Desktop Enterprise Solutions 21.0 version (V31.0D R6 05/31/2021 last update) and I am not doing anything for this to happen. It's only happening to 2 customers and it's happening EVERY single time!

It's becoming very very time consuming because these customers have several invoices as it is! 

I think it's a bug from the update in May 2021. 

Please advise. 

Thanks for giving details about your invoice number issue, @Kelly_T. I'd be happy to assist you in fixing the duplicate numbers.

You can manually edit the invoice to enter the correct number. To do this, we can pull up a report to see all the list of invoices and locate those that have duplicate numbers. Before performing the steps, I suggest creating a backup copy of your file in case of data loss or damage. When done, please follow these steps:

1. Open your QuickBooks Desktop (QBDT) program and click the Reports tab.
2. Hover over to the Customers & Receivables section and choose Transaction List by Customer.
3. Then, select the Customize Report button. Set the date to All.
4. Next, go to the Filter tab and search for the Transaction Type option.
5. Choose Invoice and click OK.
6. Once done, locate the duplicates and double-click to open.
7. Then, input the correct invoice number and select Save & Close. 

After that, let's update your invoice settings to prevent having duplicate numbers in the future. Let me guide you how:

1. Navigate to the Edit tab and click Preferences.
2. Next, click the Sales & Customers menu.
3. Select Company Preferences.
4. In the Sales Forms box, check the Warn about duplicate invoice numbers option. 
5. Then, click OK.

Once finished, let's now create a test invoice to check if the number will follow the last invoice number in the report.

If you still experience the same thing, you can use the Verify and Rebuild Data Utility tool to verify and fix possible data issues. 

QBDT makes it easy to process your customer's payments. You can send them an invoice that they can pay online or manually record the payment. To know more details about this, feel free to open this article: Receive and process payments in QuickBooks Desktop.

You can count on me if you have additional concerns about having duplicate invoice numbers in QBDT. I'd be glad to help you further. Have a good one. 

Hi, 

Thank you for responding back so fast!

I completely forgot that the issue isn't duplicate invoice numbers, it's duplicate invoices with different invoice numbers on different days. It's only happening to two customers, who are related - separate accounts but we have to change invoices from one customer to the other because they were billed to the wrong entity. 

So could that have something to do with QBs desktop changing the customer from one to another because these two customers are the only ones we have to fix. 

Below are two invoices, one is voided because it was a duplicate of another invoice from another day. 

Thanks again for your help!

Kelly 

Thank you for the prompt reply, @Kelly_T. I appreciate the details you included in your post. I'll help you out with this concern. 

You can follow the suggestion by my peer @DivinaMercy_N above, which is to run the Verify and Rebuild Data tools. 

In case you missed it, here's how to Verify Data:

1. Go to the File menu.
2. Highlight Utilities, then select Verify Data.

If the tool detects any data damage, proceed with Rebuild Data:

1. Click the File menu.
2. Highlight Utilities, then select Verify Data.

Check out this article for more information about resolving this type of situation: Resolve Potential Data Issues in QuickBooks Desktop. 

If you continue to experience the same issue after running the tools above, feel free to contact our Technical Support team for further assistance. They can pull up your account within a secure environment and investigate this issue for you. Please take note of their operating hours, so you know when they're available. 

Don't hesitate to leave a comment below if you have other concerns with duplicate invoices in QBDT. I'll be sure to get back to you. Have a great day!

The problem is we have 20 users in multi-user mode run on our server, so I guess I'll have to have our IT guy do this on a weekend because in order to do what you suggested we have to be in single-user mode. 

Our file is HUGE - over 2GB!!! 

If there's any other way to fix this issue other than verifying data, I'd be greatly appreciative.