Unity Hub 0.12.0 would not let me create a Unity Project where I have other existing projects.
I was subsequently able to create a project in the same path with Unity 2017.3.1f1
The error was: “Project path is invalid - make sure you are not using invalid characters”
my attempted path was:
D:[projects][gdrive][augmented]\cloud.storage\projects\Unity\Unity-2017.3.1f1\
~ marshall