I have successfully installed Virtualenv 12.1.1 using this manual https://virtualenv.pypa.io/en/latest/installation.html and this source file: https://pypi.python.org/pypi/virtualenv/12.1.1#downloads $ curl -O https://pypi.python.org/packages/source/v/virtualenv/virtualenv-12.1.1.tar.g... $ tar xvfz virtualenv-12.1.1.tar.gz $ cd virtualenv-12.1.1 $ python setup.py install Now 'buildout' command completes successfully. I have no time to check if everything installed correct right now but I will do it later today. I think this virtualenv problem should be reflected in the installation manual. -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1445764 Title: "The executable /usr/bin/python3.4 does not exist" error when Installing Mailman 3 on Centos 7 To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1445764/+subscriptions