【anaconda】Collecting package metadata (current_repodata.json): failed / Solving environment: failed

一、问题

• win10下，安装完conda之后打算安装pytoch时报错，解决步骤里面讲了我的多种尝试，应该可以解决此类大部分问题。

二、解决步骤

（1）步骤一

刚安装完conda之后打算安装pytoch时：

• 命令行：

PS C:\Users\25387> conda install pytorch torchvision cudatoolkit=10.2 -c pytorch

• 报错

Collecting package metadata (current_repodata.json): failed

CondaHTTPError: HTTP 000 CONNECTION FAILED for url <https://conda.anaconda.org/pytorch/win-64/current_repodata.json>
Elapsed: -

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.
'https://conda.anaconda.org/pytorch/win-64'

（2）步骤二

参考Collecting package metadata (current_repodata.json): failed之后按以下操作将文件粘贴过去：

当在windows下面的Anaconda的命令行中运行 conda时，如果出现Collecting package metadata (current_repodata.json): failed
的错误提示，可以按照下面的方式来解决掉：把路径“Anaconda3/Library/bin ”下面的文件复制到路径“Anaconda3/DLLs”下:
libcrypto-1_1-x64.dll
libssl-1_1-x64.dll

• 再次运行命令行：

PS C:\Users\25387> conda install pytorch torchvision cudatoolkit=10.2 -c pytorch

• 报错

Collecting package metadata (current_repodata.json): done
Solving environment: failed with initial frozen solve. Retrying with flexible solve.
Collecting package metadata (repodata.json): done
Solving environment: failed with initial frozen solve. Retrying with flexible solve.

PackagesNotFoundError: The following packages are not available from current channels:

  - cudatoolkit=10.2

Current channels:

  - https://conda.anaconda.org/pytorch/win-64
  - https://conda.anaconda.org/pytorch/noarch
  - https://mirrors.ustc.edu.cn/anaconda/pkgs/free/win-64
  - https://mirrors.ustc.edu.cn/anaconda/pkgs/free/noarch
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge/win-64
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge/noarch
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/win-64
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/noarch

To search for alternate channels that may provide the conda package you're
looking for, navigate to

    https://anaconda.org

and use the search bar at the top of the page.

（3）步骤三

根据博客conda安装环境报错：Solving environment: failed with initial frozen solve.的步骤：

• 查一下conda版本：conda -V
• 更新conda到最新版本：conda update -n base conda
• 查一下conda版本：conda -V
• 第二次更新conda到最新版本：conda update -n base conda
• 多等一会儿
• 然后执行：conda update --all
• 再运行之前的程序，如果可以，问题解决。

（4）步骤四

• 如果还没有解决，进行以下步骤：
• 有可能是在安装anaconda时错误，建议重装一遍anaconda，勾选自动添加环境就变量的选项。
• 运行命令行，报以下错误，也有可能是在安装cuda和cudnn时，出现的错误，我在安装cudnn时，直接将配置文件复制到了cuda中，覆盖了其中的两个文件，后来重新安装了cuda，问题的到了解决。

PS C:\Users\25387> conda install pytorch torchvision cudatoolkit=10.2 -c pytorch

Collecting package metadata (current_repodata.json): done
Solving environment: failed with initial frozen solve. Retrying with flexible solve.
Collecting package metadata (repodata.json): done
Solving environment: failed with initial frozen solve. Retrying with flexible solve.

PackagesNotFoundError: The following packages are not available from current channels:

  - cudatoolkit=10.2

Current channels:

  - https://conda.anaconda.org/pytorch/win-64
  - https://conda.anaconda.org/pytorch/noarch
  - https://mirrors.ustc.edu.cn/anaconda/pkgs/free/win-64
  - https://mirrors.ustc.edu.cn/anaconda/pkgs/free/noarch
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge/win-64
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge/noarch
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/win-64
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/noarch

To search for alternate channels that may provide the conda package you're
looking for, navigate to

    https://anaconda.org

and use the search bar at the top of the page.

• 对cuda进行环境变量设置参考博客：Win10上安装CUDA和CUDNN
• 环境变量配置好如下：
  

（5）另外的解决办法一：pip安装

• 不得已的办法：使用pip安装

pip install torch===1.5.0 torchvision===0.6.0 -f https://download.pytorch.org/whl/torch_stable.html

（6）另外的解决办法二

• 解决方法链接： Anaconda使用conda连接网络出现错误

• 链接：解决办法

• 将用户目录下的：.condarc改为如下所示，改为如下：

channels:
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/pytorch/
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main/
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/
  - defaults
  
proxy_servers: 
    http: socks5://127.0.0.1:1080

ssl_verify: False
show_channel_urls: True
allow_other_channels: True

（7）另外的解决办法三：更改镜像源

• 问题：

An HTTP error occurred when trying to retrieve this URL.

• 解决办法：
• 如果给 Anaconda 配置了环境变量，可以直接在 cmd 窗口中执行；如果没有配置环境变量，则在 Anaconda Prompt 中执行，如果没有配置环境变量，在Anaconda Prompt 中执行如下命令，为 Anaconda 配置清华大学镜像源

conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/msys2/
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge/
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/
conda config --set show_channel_urls yes

• 或者将用户目录下的：.condarc改为如下所示，更改镜像源

channels:
  - conda-forge
  - https://mirrors.ustc.edu.cn/anaconda/pkgs/free/
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge/
  - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/
show_channel_urls: true

三、参考

• Collecting package metadata (current_repodata.json): failed
• conda安装环境报错：Solving environment: failed with initial frozen solve.
• Anaconda使用conda连接网络出现错误
• Anaconda 报错Multiple Errors Encountered 或 Anaconda An HTTP error occurred when trying to retrieve th
• Win10上安装CUDA和CUDNN - 最新版的cuda和cudnn安装教程，优先。