After you file
If you're using TurboTax Desktop, go to FORMS at the upper right, and then Open Form, Schedule D. You can make changes directly on the form, or Delete the Form from the bottom of the page.
If in TurboTax Online, go to Tax Tools > Tools in the left-side menu, then choose Delete a Form from the pop-up menu. When you see the list of forms displayed, scroll to Schedule D and choose Delete at the far right.
However, you can also go to Wages &Income > Investment Income, and see if you have an Untitled item with a $0 value and use the trash can icon to delete it.
