I hope @JamalNUMAN found a solution to this...
I'm using ArcMap 10.6 for university projects and after importing data to explore, I want to remove it and go back to the "Blank Slate" with Unknown Units to then explore other data.
Currently, I have to open a new blank template or seeming risk my next imported data be projected onto the (now) default coordinates of the data that has been removed?
any help is really appreciated! I'm still very inexperienced with the software 😑