While installing TensorFlow on a Mac running El Capitan I kept getting one of those crazy Python errors that are impossible to decipher. Thanks to Stackoverflow which always saves me while coding I found out the problem. It is apparently “due to the System Integrity Protection introduced in OS X El Capitan.” The fix is copied below for the next time I run into this error. Thank you for the tip Kof.
sudo pip install --upgrade $TF_BINARY_URL --user python