title: PyInstaller failing to include some modules from C:\Python27\Lib
body: <p>I've been repeatedly making good PyInstaller executables of a Tkinter utility program, and suddenly this morning the resulting executable fails with a "can't import" error for modules in C:\Python27\Lib, such as "timeit" and "bisect".</p>
  
  <p>The script runs fine on its own. Only the executable has problems.</p>
  
  <p>Any ideas what could have changed to cause this behavior?  Or how to force a fix?</p>
  
  <p>[EDIT]  Here's the specific error reported by the executable:</p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;string&gt;", line 35, in &lt;module&gt;
    File "../..\utils\InterpolatedArray.py", line 12, in &lt;module&gt;
      import bisect
  ImportError: No module named bisect
  </code></pre>
  
  <p>When I comment-out the use of this module (to bypass the import of bisect), it next fails on an import of timeit.  None of these errors occur when running the script itself.</p>
  
  <p>[EDIT2]  Pyinstaller creates the directories it needs (./build and ./dist), and has no permission problems.  The pyinstaller build completes without error.</p>
  
  <p>[EDIT3]  Here's the build command I'm using:</p>
  
  <pre><code>pyinstaller -F MyMainModule.py
  </code></pre>