I have installed python 3.5.4 on my windows computer. My MATLAB 2017a supports 2.7, 3.4 and 3.5 versions of Python. After installing python 3.5.4, when I type 'pyversion' in command window, I get the answer "Cannot find a default python". Intially MATLAB was showing the python version (by typing pyversion) but after restarting it is giving above mentioned error. Kindly help me to resolve this issue.