If you used TurboTax Canada TurboTax Do It Yourself (Online), you must open another return if the return that you want to delete is the last one that you worked on. If you have no other returns, then you'll need to start a blank return before you can delete it.

To start a new return, select “Start a New Return” from under “My Returns” in the bottom left corner. Once you have started your new return, you can select “View All Returns” from under “My Returns”. Then delete the unwanted return by clicking the small Trash Can next to it or “Delete” under the return’s name.

Please see this TurboTax Canada FAQ for more information on who can use Free: Who can file for free using TurboTax?