Can I make a “paid” invoice “unpaid again? I am trying to clear the payment and have the invoice go back to unpaid. How do i mark the invoice unpaid again?

Thanks for bringing this to my attention, @PositivePPW. Let me guide you to mark the wrong paid invoice as unpaid so you can link the payment to the correct invoice.

In QuickBooks online, you can change the status of an invoice by deleting the payment link to it. To do so, you can follow the steps below as your guide:

1. Go to Sales, then select All Sales.
2. Locate the invoice you want to change the status, then click Edit.
3. On the PAID payment status section, click on the 1 Payment made.
4. Click the Date hyperlink to route you to the Receive Payment page.
5. Click Clear Payment.
6. On the More button, select Delete.
7. Click Yes to confirm.

On the other hand, if this doesn't work and you still receive the same error message, I recommend performing some troubleshooting steps to see if the problem is due to a cache-induced browser. You can start by accessing your account in an incognito or private browser. Please refer to the keyboard shortcuts below:

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Microsoft Edge: Ctrl + Shift + P
• Safari: Command + Shift + N

Follow the steps I provided previously and see if you can delete the payment. If it works, you can clear your browser's cache to remove them and start with a clean slate.

Once done, you may record a received payment and link it to the correct invoice. 

In addition, you can run a Transaction List by Customer report to have a full view of all transactions made within QuickBooks. 

Keep us posted if you have other concerns about changing invoice status in QuickBooks or other inquiries related to the program. We've got your back and we'll be here to lend you a hand. Have a great day ahead!