Is it possible to delete a draft tax return when using Turbotax software on an iMac? I accidentally created two separate returns.

Yes, you should be able to delete a tax return when using TurboTax software on an iMac.  To do so, follow these steps:

• Launch TurboTax
• Click once on the return you don't want and a border will appear around the icon.   
• Click the DELETE key on your computer.  A popup will ask you if you want to delete it from the TurboTax program, or if you want to delete it from your computer.  To completely delete it, be sure you choose "Delete from TurboTax AND your computer".

Thanks, but this solution did not work for me.  I have an iMac Retina 4K Desk Top computer, not a laptop, if that makes a difference.  The delete key suggestion did not work.  However, I was able to move the highlighted document and send to trash.  But as I moved one of the highlighted documents, all documents, including my original were deleted.  Even Time Machine could not bring back my original document, just one of the empty documents.  In retrospect, my problem was with confusion of unwittingly saving documents with different names.  So, I deleted Turbotax, reinstalled, and started from scratch.  Frustrating.