(big help from http://zaidox.com/os-x-mavericks-virtualenv-and-pip.html, seems this was a common problem)
Just to document the issue I had with my local pip, python and virtualenv setup after updating my Mac to 10.10 Yosemite.
A few things I saw initially:
Virtual env seemed to disappear
/usr/bin/python: No module named virtualenvwrapper virtualenvwrapper.sh: There was a problem running the initialization hooks.
If Python could not import the module virtualenvwrapper.hook_loader, check that virtualenv has been installed for VIRTUALENVWRAPPER_PYTHON=/usr/bin/python and that PATH is set properly. jbk[~] $ setup /usr/bin/python: No module named virtualenvwrapper /usr/bin/python: No module named virtualenvwrapper
Pip was broken
$ pip dyld: Library not loaded: @executable_path/../.Python Referenced from: /Users/jkeesh/.virtualenvs/codehs/bin/python Reason: image not found Trace/BPT trap: 5
Pip referenced an old python
$ pip -bash: /usr/local/share/python/pip: /usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/Resour: bad interpreter: No such file or directory
Python current version was 2.7.6 though the old one seemed to be
2.7.jbk[~/Downloads] $ python Python 2.7.6 (default, Sep 9 2014, 15:04:36) [GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.39)] on darwin Type “help”, “copyright”, “credits” or “license” for more information. >>>
The Fix
I had an issue in my PATH variable adding an extra path to the PATH. I removed this from my bashrc
/usr/local/share/python
Then re-installed pip and reinstalled virtual env.