Hi there, Yvonne18.

I'd like to know if you have utilized the Simple and Advance Find features by pressing Ctrl + F suggested by my colleague when searching for the existing invoice in your QuickBooks Desktop (QBDT).

If so, then you haven't found any transaction with an identical invoice number. Let's perform troubleshooting in your company file by utilizing the verify and rebuilding feature of QBDT, as this helps situate the data issue that causes this error with your invoices.

To begin, let's start verifying your company file data. Kindly follow the steps provided below:

1. Go to Window, then select Close All.
2. Go to File, then choose Utilities.
3. Select Verify Data. If you see:

• QuickBooks detected no problems with your data — your data is secure, so you don't need to do anything else.
• If you see an error message – you can search on our QBDT support site to learn how to fix it.
• If your data has lost integrity – damage to your data was found in the file and we have to rebuild your data.

Moreover, if you need to rebuild the data in your company file, see the step-by-step guidelines beneath:

1. Go to File, then select Utilities.
2. Click on Rebuild Data.
3. Follow the on-screen instructions, then press OK.
4. Select the place where you want your backup file to be saved, then tap OK.
5. Enter a new name in the File name. Click Save.

You can refer to the article below that provides detailed instructions on the steps I outlined earlier: Verify and Rebuild Data in QuickBooks Desktop.

However, if you have found an invoice after using the Simple and Advance Find features, you can change the previous invoice number on your transaction or the new invoice you just created to avoid duplicate transactions.

In addition, once your transactions are ready, familiarize the process of reconciling your QBDT account to see how to match your credit card and bank statements: Reconcile an account in QuickBooks Desktop.

Reach back to us if you have additional concerns with your invoices or any QBDT-related inquiry, Yvonne18. The Community will be here to address them once we get your response.