I have a Mac running OS X 10.11.6, Python 3.5.2, and fish 2.3.1. I installed Python 3.6.0, and everything seemed to work fine. However, I typed "python3" in my shell and it started Python 3.5.2.

I restarted my shell and typed "python3", and it still started Python 3.5.2. I ran "which python3" and it told me "/Library/Frameworks/Python.framework/Versions/3.5/bin/python3".

I ran "echo $PATH" and it told me "/Library/Frameworks/Python.framework/Versions/3.5/bin", among other directories that seem unrelated to Python.

I thought that maybe the installer updated my ~/.bash_profile, assuming that I am using bash like most people, but I looked in that file, and the only things affecting my path that look Python-related are adding the directories "/Library/Frameworks/Python.framework/Versions/2.7/bin" and "/Library/Frameworks/Python.framework/Versions/3.5/bin".

I re-ran the installer, clicked the "Customize" button, made sure that the "Shell profile updater" checkbox was checked, and ran "python3", and it started Python 3.5.2.

I can probably fix this by adding the right directory to my $PATH, but I think it is a bug if the installer doesn't make that change for me, or even try to make the change.