I have something similar. I was helping my nephew with his 2020 taxes and in the course of the interaction, he showed me his t5008 email from his broker for 2019 (electronic copy only). When I entered the many, many lines on his original return (to see the results), he ended up with a loss. How do I file a T1-ADJ when both the initial amount and final amount for the line is zero? Can I go to the 2019 filing I changed and do a reFile? Or do I just print off the schedule and mail in the 3 pages attached to the paper copy of the T1-ADJ with zeros? Assistance would be greatly appreciated.