title: Pipenv-Error: ModuleNotFoundError: No module named 'pip._internal'
body: <p>Today, I installed Pipenv via </p>
  
  <p><code>pip install pipenv</code></p>
  
  <p>As mentioned in the documentation I went to a test directory and created a new virtual environment using </p>
  
  <p><code>pipenv shell</code> </p>
  
  <p>and tried to install a package via </p>
  
  <p><code>pipenv install numpy</code></p>
  
  <p>I got the following error message:</p>
  
  <pre><code>Installing numpy…
  ⠧
  Error:  An error occurred while installing numpy!
  Traceback (most recent call last):
    File "/Users/florian/.local/share/virtualenvs/test-bJfQ6Jzk/bin/pip", line 7, in &lt;module&gt;
      from pip._internal import main
  ModuleNotFoundError: No module named 'pip._internal'
  </code></pre>
  
  <p>This error occurs even after reinstalling pipenv, deleting all files and recreate the environment. It also had no impact if I ran <code>pipenv install numpy</code> inside or outside the environment.</p>
  
  <p>Python 3.6.3<br>
  Pipenv 11.10.1</p>
  
  <p>Thank you in advance.</p>