How to minimize unity3d application to tray? Is it possible?
No, Unity does not provide an option for minimizing to the system tray.
Though I believe that there are applications available which allow you to add such functionality to almost any Windows program.
In fact a quick search on Google revealed several applications which claim to do just this. Here is the first result which I grabbed from the Google search results:
4t Tray Minimizer Free/Pro - Minimize any application to system tray!