Posting files with the default origin of First Procedure UCS is the most common choice.  It can be made the default setting by using a custom NC Setup you make.

1).  Open a NEW empty NC file.
2).  Create an NC Setup and edit it.
3).  Select the icon to choose a Post Processor.
4).  In the post dialog window select a post.  (Any post will do, just pick the one that you use the most.)  Now switch the reference UCS to First Proccedure UCS.  Exit the post window and save and exit the NC setup definition.
5).  In the NC process manager window, right click on the NC Setup and select Templates-Save Templates.  Switch the file type to .mtt, give it a name, and save this template.
6).  Go to Preference function, and open the the General > GeneralNC preference.  Check the box to Auto-Load Default Template.  Navigate to the folder where the .mtt template was saved and select it.  Save and exit the preferences.

Any NEW NC file will now start with the NC setup that correctly chooses the First procedure UCS as the post origin. 

*Note: NC setup is useful for MANY types of time saving default settings.  Explore the functionality here, or view our webinar on NC setup for more.