EDIT: conda install pytorch==1.0.0 torchvision==0.2.1 -c pytorch failed with this error. This is very frustrating.
pytorch-1.0.0        | 605.7 MB  | ###########################################################################9 | 100% WARNING conda.gateways.disk.delete:unlink_or_rename_to_trash(143): Could not remove or rename C:\Users\User\anaconda3\pkgs\pytorch-1.0.0-py3.7_cuda90_cudnn7_1\Lib\site-packages\torch\lib\libprotobuf.lib.  Please remove this file manually (you may need to reboot to free file handles)
WARNING conda.gateways.disk.delete:unlink_or_rename_to_trash(143): Could not remove or rename C:\Users\User\anaconda3\pkgs\pytorch-1.0.0-py3.7_cuda90_cudnn7_1\Lib\site-packages\torch\lib\libprotobuf.lib.  Please remove this file manually (you may need to reboot to free file handles)
InvalidArchiveError(‘Error with archive C:\Users\User\anaconda3\pkgs\pytorch-1.0.0-py3.7_cuda90_cudnn7_1.tar.bz2.  You probably need to delete and re-download or re-create this file.  Message from libarchive was:\n\nCould not unlink’)