I have 2 python versions installed under my mac osx sierra: python 3.5 python 2.7
I installed pyinstaller under python3.5 with this command:
python3
PyInstaller is case sensitive when being executed from the python3 - m method. You need to run it as follows.
python3 -m PyInstaller yourscript.py
If you want directly execute from the terminal you need to install it as follows.
python3 -m pip install pyinstaller or pip3 install pyinstaller
Following that, you need to set your global python executable to python3.
pyinstaller yourscript.py