For sites with poor Internet connection, conda install mypkg will fail and not resume a partially downloaded package. Workaround: use URL from the error message with cURL to download the package and install directly.

curl -L -O -C https://conda.anaconda.org/conda-forge/win-64/<package file>

Resume download interrupted by reissuing the command to resume download. Install from the tar.bz2 file by

conda install <package stem>.tar.bz2