title: How to troubleshoot python import error - DLL access denied
body: <p>I have installed a certain python package (netCDF4), which contains compiled code (extension module). I am running Anaconda and python 3.6 under Windows 10 (x64). When importing the module from console, I get the following error:</p>
  
  <pre><code>In [1]: import netCDF4
  ---------------------------------------------------------------------------
  ImportError                               Traceback (most recent call last)
  &lt;ipython-input-1-9588a3d4fb24&gt; in &lt;module&gt;()
  ----&gt; 1 import netCDF4
  
  C:\Program Files\Anaconda3\lib\site-packages\netCDF4\__init__.py in &lt;module&gt;()
        1 # init for netCDF4. package
        2 # Docstring comes from extension module _netCDF4.
  ----&gt; 3 from ._netCDF4 import *
        4 # Need explicit imports for names beginning with underscores
        5 from ._netCDF4 import __doc__, __pdoc__
  
  ImportError: DLL load failed: Access is denied.
  </code></pre>
  
  <p><em>But the module is loaded flawlessly from an administrator account.</em></p>
  
  <p>I suspect that some crucial DLL file is blocked by company-wide security policy, which is quite restrictive. For instance, binary files are blocked by default unless in the "program files" folder. But my python distribution and the netCDF4 package are already within this folder, so I'm at loss how to explain this. The AppLocker log in Windows Event Viewer does not show any blocking activity. The dependencies listed by the depencency walker tool are either system libraries or contained in the "program files" folder.</p>
  
  <p>How do I start troubleshooting? How can I find out what is going on?</p>