title: Mac Python "Installation step failed: run postflight script"
body: <p>I'm new to Python development, and in trying to get Aptana Studio Setup, I seemed to have messed up my Python install.  So I followed the uninstall MacPython instructions here <a href="http://homepages.cwi.nl/~jack/macpython/uninstall.html" rel="nofollow">http://homepages.cwi.nl/~jack/macpython/uninstall.html</a></p>
  
  <p>...and now I'm trying to install Python again.</p>
  
  <p>From what I can tell, GAE needs you to have Python 2.5. So I'm trying to install the 2.5.4 release from here: <a href="http://www.python.org/download/releases/2.5.4/" rel="nofollow">http://www.python.org/download/releases/2.5.4/</a> I've downloaded the dmg and when installing I get the following error:</p>
  
  <pre><code>The installation failed.
  
  The following installation step failed: run postflight script for Fix system Python. Contact the software manufacturer for assistance
  </code></pre>
  
  <p>In fact, I've tried 2.5, 2.6 and 2.7 dmg installers for python, and I got the same exact error when installing all 3.</p>
  
  <p>I'm running OS 10.6.8</p>
  
  <p>Any ideas? Is there a better/different way to install Python on a Mac?</p>
  
  <p>UPDATE:
  When I open up my installer log, here are a few problems that I see:
  I got a lot of these type of errors:</p>
  
  <pre><code>Sep 19 14:04:39 thething pkgExtractor[1689]: BomFatalError - cpio read error: bad file format
  Sep 19 14:04:39 thething pkgExtractor[1689]: Package Authoring Error: Package "PythonSystemFixes-2.6.pkg" is using a deprecated archive format. Running in compatibility mode.
  </code></pre>
  
  <p>And at the end I got this:</p>
  
  <pre><code>Sep 19 14:04:40 thething Installer[1641]: run postflight script for Fix system Python
  Sep 19 14:04:40 thething runner[1657]: postflight[1722]: Could not find platform independent libraries &lt;prefix&gt;
  Sep 19 14:04:40 thething runner[1657]: postflight[1722]: Consider setting $PYTHONHOME to &lt;prefix&gt;[:&lt;exec_prefix&gt;]
  Sep 19 14:04:40 thething runner[1657]: postflight[1722]: 
  Sep 19 14:04:40 thething runner[1657]: postflight[1722]: 'import site' failed; use -v for traceback
  Sep 19 14:04:40 thething runner[1657]: postflight[1722]: Traceback (most recent call last):
  Sep 19 14:04:40 thething runner[1657]: postflight[1722]:   File "/Volumes/Python 2.6.6/Python.mpkg/Contents/Packages/PythonSystemFixes-2.6.pkg/Contents/Resources/postflight", line 16, in &lt;module&gt;
  Sep 19 14:04:40 thething runner[1657]: postflight[1722]:     import os
  Sep 19 14:04:40 thething runner[1657]: postflight[1722]: ImportError: No module named os
  Sep 19 14:04:40 thething runner[1657]: postflight[1722]: 
  Sep 19 14:04:40 thething Installer[1641]: Install failed: The following installation step failed: run postflight script for Fix system Python. Contact the software manufacturer for assistance.
  Sep 19 14:04:40 thething Installer[1641]: IFDInstallController 207240 state = 7
  Sep 19 14:04:40 thething Installer[1641]: Displaying 'Install Failed' UI.
  Sep 19 14:04:40 thething Installer[1641]: 'Install Failed' UI displayed message:'The following installation step failed: run postflight script for Fix system Python. Contact the software manufacturer for assistance.'.
  </code></pre>