I just allowed the latest update to happen on my 2019 version, now I can't have 2019 open at the same time as 2017. I can have 2020 open at the same time as 2019 or  2017, but I cannot open 2017 and 2019 at the same time! Is this what you are referring to? What a pain in the butt... I have 6 companies that I maintain with different versions of QB and have always had three open at once, which makes it very easy... something in the last update created this new issue. Anybody else?