Anaconda wants to update itself and use new version of python. Usually I don’t touch my base environment and just let anaconda update it. I don’t install any extra packages into the base environment.
If I want to run a script that needs an old version of python, I create a new environment with that old version, and then use this new environment to run the script:
conda create --name py2 python=2.7 conda create --name py3 python=3.5
CLICK HERE to find out more related problems solutions.