I have a single .mxd file that, when opened, creates a projection file (.prj) in the same folder as the .mxd file. This does not happen with other .mxd files.
This projection file is called ".prj" (not including the quotation marks).
The .mxd file's data frames (2) also have CRS defined (same for both).
However, the ".prj" file does not contain the typical WKT and EPSG information (I half expected it to include the information relevant to the CRS's in defined in the .mxd file). Instead, it just shows the following...
Projection GEOGRAPHIC Datum NAD83 Spheroid GRS80 Units DD Zunits NO Parameters
...which seems to me like a broken projection file.
What setting is turned on in this .mxd that makes this happen?