New issue 662: Use pip to manage pure python dependencies in the install script https://bitbucket.org/yt_analysis/yt/issue/662/use-pip-to-manage-pure-python... Nathan Goldbaum: I believe that was the cause of Mark Krumholz's issue in this thread: http://lists.spacepope.org/pipermail/yt-users-spacepope.org/2013-September/0... This is a somewhat dramatic change compared to what we currently do in the install script, but I think it's necessary. Another option would be to make `yt update --all` a bit smarter or have it `pip uninstall` outdated python packages.