I was both the owner and administrator on my Windows 10 Pro version 1909 Computer. The fix I found was that I had to create a new user and make them/it the administrator, then reboot computer. Install Turbo Tax 2019 as the original boot up user... not administrator. You will be asked for administrator's permission, give it and continue install. This worked for me and also some other programs I had problems installing now installed as well. (Nero 2016 and Blackberry desktop software are examples that myself and other people have a problem with as well. They both install now on my Windows 10 Pro version 1909 computer. ) I hope this is also a fix for other users as well.