I had the same exact problem. I tried tech support but they were useless. I realized I was wasting my time trying to get it to work. I made a copy of the 2017 file with a different name. I did proforma to 2018, then I input my 2018 transactions so new file matched actual tax return. I then proforma that new file to 2019 and it worked. It's not the perfect solution but it was quicker than creating completely new file. Hope it helps.