There are a couple of things going on here. First, arcpy.GetInstallInfo has no parameters. It will accept an argument and not throw an error, but any argument that is passed doesn't affect the results of what is returned. The arcpy.GetInstallInfo function gets the installation information that relates to the currently loaded ArcPy site package, which in your case is ArcGIS Engine.
If you install ArcGIS Desktop and ArcGIS Engine on the same machine using standard installation instructions, the two will share a single Python interpreter, usually C:\Python27\ArcGIS10.x (10.2 in this case). Another way to look at it is that a single Python interpreter has 2 ArcPy site packages registered/installed. Since the site packages have the same name (arcpy), they both can't be loaded into the interpreter at the same time. When the interpreter encounters an import arcpy statement, it will find and import whichever site package is found first in the search path for modules, i.e., sys.path.
Before importing ArcPy, you can quickly determine which ArcPy site package will be loaded by running:
import imp
imp.find_module('arcpy')In this case, the result will come back with ...\Engine10.2\... since it comes first in the sys.path. Reversing the order of sys.path before importing ArcPy will likely find and import the Desktop site package for your situation.
import imp
import sys
sys.path.reverse()
imp.find_module('arcpy')The issue with reversing sys.path out of hand is that it will import the Engine-based site package if ArcGIS Engine was installed first. There are a couple of more thoughtful ways to get around this problem. First, setting the PYTHONPATH Windows environment variable to the Desktop-based site package will ensure that it is loaded first regardless of the sys.path order. However, in this case, it seems you don't already know that location and am trying to figure it out. A second approach would be to remove all of the Engine-related entries in sys.path before import arcpy.
import sys
for p in sys.path[:]:
if 'Engine' in p:
sys.path.remove(p)
If the goal is to determine whether ArcGIS Desktop is installed and where, maybe querying a WMI service for installed applications and information is a better approach. Adapted from the Microsoft Script Center List Installed Software Python script:
import win32com.client
objWMIService = win32com.client.Dispatch("WbemScripting.SWbemLocator")
objSWbemServices = objWMIService.ConnectServer(".", "root\cimv2")
colItems = objSWbemServices.ExecQuery("Select * from Win32_Product "
"where Name Like 'ArcGIS % for Desktop'")
for objItem in colItems:
print "Name: ", objItem.Name
print "Install Date: ", objItem.InstallDate
print "Install Location: ", objItem.InstallLocation
print ""
