title: Anaconda unicode error on command line startup on Windows
body: <p>I got this error when running python from command line on Windows 10:</p>
  
  <pre><code>C:\Users\windows&gt; python
  Python 3.6.5 |Anaconda, Inc.| (default, Mar 29 2018, 13:32:41) [MSC v.1900 64 bit (AMD64)] on win32
  Type "help", "copyright", "credits" or "license" for more information.
  Failed calling sys.__interactivehook__
  Traceback (most recent call last):
    File "C:\ProgramData\Anaconda3\lib\site.py", line 410, in register_readline
      readline.read_history_file(history)
    File "C:\ProgramData\Anaconda3\lib\site-packages\pyreadline\rlmain.py", line 165, in read_history_file
      self.mode._history.read_history_file(filename)
    File "C:\ProgramData\Anaconda3\lib\site-packages\pyreadline\lineeditor\history.py", line 82, in read_history_file
      for line in open(filename, 'r'):
    File "C:\ProgramData\Anaconda3\lib\encodings\cp1252.py", line 23, in decode
      return codecs.charmap_decode(input,self.errors,decoding_table)[0]
  UnicodeDecodeError: 'charmap' codec can't decode byte 0x81 in position 991: character maps to &lt;undefined&gt;
  </code></pre>
  
  <p>I have not changed anything about my python environment, I was just running some scripts that I've been working on for the last week. I honestly have no idea where this could be coming from; it seems to be an issue when python reads in its history. Updating python and conda did nothing. I found a very similar issue on a Chinese site <a href="https://ask.hellobi.com/question/24842" rel="noreferrer">here</a> but the solution is unhelpful.</p>
  
  <p>At the moment, I cannot find any issues when continuing to run python or my scripts, but I don't want this to come back and bite me. Any help is appreciated!</p>