The case of Error 2000 Failed creating scripting engine XSI.SIPython.1

The guy sitting next to me kept getting this Python error at startup (which meant I had to either fix his install or continue taking all the CrowdFX cases 😉

' ERROR : 2000 - Failed creating scripting engine: XSI.SIPython.1.
' pythoncom error: PythonCOM Server - The 'win32com.server.policy' module could not be loaded.
' <type 'exceptions.ImportError'>: No module named win32com.server.policy
' pythoncom error: CPyFactory::CreateInstance failed to create instance. (80004005)

This happened only with the Python installed with Softimage. We did runonce.bat. We checked that Python was in the PATH. I scoured a Process Monitor log for several hours. But no luck. After a few days off, I came back and took another look at his Process Monitor log, and I noticed that at a certain point, Softimage switched over to reading files from the system Python install (in C:\Python26). And that was the clue.

It turns out that the environment variable PYTHONHOME was set to C:\Python26. Unsetting that environment variable was the solution.

Setting PYTHONPATH to C:\Python26 also causes the same error.