You can mark it as unpaid by removing the payment or credit that was applied to the invoice, @chrisstuttard1985.

Here’s how you can do it:

1. Go to the Sales menu and find your invoice under Invoices.
2. Open the invoice that’s marked as paid. Scroll down to check if there’s a payment or credit linked to it.
3. Click on the linked payment to open its details. From here, you can choose to Delete Payment or Remove the transaction linked to the invoice.
4. Once the payment or credit is removed, QuickBooks will automatically update the invoice status to unpaid.

You can save the invoice afterward, and the unpaid status will reflect.

Let us know if you have any other questions or need further help.