Creating the tensorflow env without the correct python version did not work for me. So I had to do the following, which worked...
>deactivate tensorflow # start by deactivating the existing tensorflow env
>conda env remove -n tensorflow # remove the env
>conda create -n tensorflow python=3.5
>activate tensorflow
i had the same problem in windows 10 and python 3.6 so i navigated to anaconda navigator ( just search anaconda navigator in start search).
in the Environment tab you can create/delete your environments. just create an environment, name it tensorflow and choose python 3.5 as python version.
then you can activate tensorflow in your command line:
activate tensorflow
and install tensorflow with :
pip install tensorflow #or tensowrlow-gpu
Maybe you are installing the wrong pre-build binary?
Check on https://github.com/lakshayg/tensorflow-build
For my Coffee Lake processor on Ubuntu 18.04 the download url was: https://github.com/lakshayg/tensorflow-build/releases/download/tf1.12.0-ubuntu18.04-py2-py3/tensorflow-1.12.0-cp36-cp36m-linux_x86_64.whl
pip install --ignore-installed --upgrade <PATH>
resolved the issue for me.