I'm running ArcMap 10.2 and just set up 'ArcGIS for Desktop Background Geoprocessing (64 bit)' and now I have both the ArcGIS10.2 folder and ArcGISx6410.2 folder inside my python folder. I have background processing enabled as well. When I open the python window inside of ArcMap and do import sys, print sys.version it shows that it is running the 32 bit version.

How do I get the 64 bit version to run inside of ArcMap?

  • Good question, maybe the version is set when actually running a process?
    – artwork21
    May 23, 2014 at 19:46
  • 6
    Because the ArcGIS applications are 32-bit, they can only run 32-bit embedded Python. Background geoprocessing runs in a separate process, so it can be 32-bit or 64-bit. Try the same test in a Python script tool, taking care to uncheck its "always run in foreground" property.
    – blah238
    May 23, 2014 at 20:04

2 Answers 2


You cannot run a 64 bit executable within a 32 bit process space. That is, the Python window in ArcMap can only ever run in 32 bits, but Geoprocessing tools called from that window can run in a 64 bit background process if background processing is turned on.

Your script tools can determine what environment they are running in by checking sys.executable


You can also try this as well:

import sys
print sys.version

for 32-bit python, you'll get something like this:

2.7.5 (default, May 15 2013, 22:43:36) [MSC v.1500 32 bit (Intel)]

for 64-bit python, it will look something like this:

2.7.5 (default, May 15 2013, 22:44:16) [MSC v.1500 64 bit (AMD64)]

  • 2
    The OP did mention they were doing exactly that already.
    – blah238
    May 29, 2014 at 21:39

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