Broken references in Virtualenvs

After trying a few things, this worked for me:

go to your virtualenv directory (but don't run workon):

cd ~/.virtualenv/name_of_broken_venv

Now delete these files:

rm -rf .Python bin/python* lib/python2.7/* include/python2.7

Then to rebuild your venv, run:

virtualenv .
workon name_of_broken_venv
pip freeze