Good day, notsyncing.

Since you're still unable to send out an invoice in QuickBooks Desktop, let's perform a clean install to resolve software issues like this. Before performing the steps, make sure you've created a backup copy.

Then, have your license and product number handy. To get this information, just press the F2 key while QuickBooks is open.

Follow these steps to uninstall QuickBooks:

1. From the Windows Start menu, search for Control Panel and click on it to open.
2. Select Programs and Features or Uninstall a Program, then choose the version of QuickBooks you're having problems with from the list of installed programs.
3. Click on Uninstall/Change and follow the onscreen instructions.

Now, download and install the QuickBooks Tools Hub. You can refer to this article for the detailed steps: Clean install QuickBooks Desktop.

If the issue persists, I recommend reaching out to our QuickBooks Technical Support Team. They have more tools to look into this further:

Here's how to contact them:

1. Open QuickBooks.
2. From the Help menu, select Support.
3. Scroll down to the Additional resources section and click on the Contact us link.
4. Choose Need to contact Intuit Support, then select either Get Phone Number or Start a Message.

Please leave a comment below if you have any other concerns or follow-ups. I'll be here to help. Have a great day.