Below are some options to finding and or creating the Projection files to use for Export of data from Trimble GPS Pathfinder Office. Or, what if you don’t have direct access to ArcGIS and would still would like to use these projections files to define the projection of your Coordinate System for your SHP file export – then what do you do? Scroll down and on the right underneath the “General Support” column look for below the GPSCorrect and GPS Analyst links and locate and click on the link called ArcGIS 10 Coordinate System Files. Tip: Remember to define the projection as the same as your coordinate system “Apples to Apples” otherwise your data might end up in another state or continent. Once you save the folder to your PC you can then Browse to the Projection folder/files you are interested in from within the GPS Pathfinder Office “SHP files Export Properties Coordinate System” tab. Side note: If you are not finding the proper “WGS84” in the projection folder then try the “Geographic projection” folder. On WinXP, it’s C:Documents and Settings[login]Application DataESRIDesktop10.1ArcMapCoordinate Systems Why doesn’t the software automatically choose the proper projection file based on the coordinate system of the output file? That would prevent data from being assigned the wrong projection. Hi, thats a great question. I don’t have an exact answer as to why Trimble does not have it programed that way. About 3 years ago this was not even an option in GPS Pathfinder Office. You would then have to assign the projection in ArcGIS. You are in control of then pointing to the ESRI projection and or Geographic files as there might be cases where you don’t want the same projection as what your coordinates are set to. Thank you so much for providing the zip file of all the .prj files! It makes my life so much easier, and I will provide a copy to my co-workers as we all transition to 10.1. Source.