最近在跑一个开源项目遇到了以下问题，查了很多资料都大（抄）同（来）小（抄）异（去）的，解决不了根本问题，费了很大的劲终于得以解决，记录如下：
1、问题及过程：
(myenv) D:\Workspace\python\XXXXX>conda install python=3.6.13
Solving environment: done
.....
Proceed ([y]/n)? y
Downloading and Extracting Packages
certifi-2021.5.30 | 142 KB | | 0%
......
CondaHTTPError: HTTP 404 NOT FOUND for url <https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main/win-64/certifi-2021.5.30-py36haa95532_0.tar.bz2>
Elapsed: 00:00.050146
An HTTP error occurred when trying to retrieve this URL.
HTTP errors are often intermittent, and a simple retry will get you on your way.
CondaHTTPError: HTTP 404 NOT FOUND for url <https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main/win-64/python-3.6.13-h3758d61_0.tar.bz2>
Elapsed: 00:00.189201
.......
An HTTP error occurred when trying to retrieve this URL.
HTTP errors are often intermittent, and a simple retry will get you on your way.
2、解决办法：
在用户目录下（如win10中C:\Users\xxx\），修改.condarc文件，内容替换如下：
channels:
- defaults
show_channel_urls: true
channel_alias: https://repo.anaconda.com
default_channels:
- https://repo.anaconda.com/pkgs/main
- https://repo.anaconda.com/pkgs/free
- https://repo.anaconda.com/pkgs/r
- https://repo.anaconda.com/pkgs/pro
- https://repo.anaconda.com/pkgs/msys2
custom_channels:
conda-forge: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud
msys2: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud
bioconda: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud
menpo: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud
pytorch: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud
simpleitk: https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud关键点在于：default_channels用的官方的源，custom_channels用的清华的源。
问题最终得以解决。
