pip upgrade fails - says "owned by OS"

pip install --upgrade six
Downloading/unpacking six from https://pypi.python.org/packages/3.3/s/six/six-1.9.0-py2.py3-none-any.whl#md5=9ac7e129a80f72d6fc1f0216f6e9627b
  Downloading six-1.9.0-py2.py3-none-any.whl
Installing collected packages: six
  Found existing installation: six 1.5.2
    Not uninstalling six at /usr/lib/python2.7/dist-packages, owned by OS
Successfully installed six
Cleaning up...

===========================================
pip 1.5.4 from /usr/lib/python2.7/dist-packages (python 2.7)
===========================================
cat lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=14.04
DISTRIB_CODENAME=trusty
DISTRIB_DESCRIPTION="Ubuntu 14.04.2 LTS"

[sahilshekhawat]

TLDR;

• You can remove previous installation via $ sudo apt-get remove python-pip or,
• You can simply force the installation via pip install --ignore-installed six

I don’t think this is a bug.This might clear the confusion: http://askubuntu.com/questions/644911/unable-to-upgrade-pip.

Theapt system and PyPI uses two different mechanisms.

This is due to the fact that six was installed via apt rather than pip.

[Egor3f]

$ sudo apt-get remove python-pip Completely solves problem for me.