First just try changing the ending .txt to .pdf.
Or download it again using a different browser and turn off your antivirus.
VolvoGirl is a genious! I changed the extension and voila! There it is. I had to change it twice but it worked. It first downloaded and added the .txt extension after I erased it and added .pdf extension. Thanks!
There may have been an issue with the file during download. You can retry downloading your tax return by: