Anaconda中无法启动Jupyter Notebook，遇环境不可用及SSL错误

刚安装Anaconda，首次启动时提示“environment is no longer available”，启动Jupyter Notebook时出现SSL相关错误，多次重装软件、执行卸载重装pyzmq及Jupyter的命令均无法解决。

报错堆栈 #

Traceback (most recent call last):
File "C:\Downloads\Anaconda3\envs\Python\Scripts\jupyter-notebook-script.py", line 6, in 
from notebook.notebookapp import main
File "C:\Downloads\Anaconda3\envs\Python\Lib\site-packages\notebook\notebookapp.py", line 59, in 
from tornado import httpserver
File "C:\Downloads\Anaconda3\envs\Python\Lib\site-packages\tornado\httpserver.py", line 32, in 
from tornado.http1connection import HTTP1ServerConnection, HTTP1ConnectionParameters
File "C:\Downloads\Anaconda3\envs\Python\Lib\site-packages\tornado\http1connection.py", line 34, in 
from tornado import iostream
File "C:\Downloads\Anaconda3\envs\Python\Lib\site-packages\tornado\iostream.py", line 40, in 
from tornado.netutil import ssl_wrap_socket, _client_ssl_defaults, _server_ssl_defaults
File "C:\Downloads\Anaconda3\envs\Python\Lib\site-packages\tornado\netutil.py", line 35, in 
_client_ssl_defaults = ssl.create_default_context(ssl.Purpose.SERVER_AUTH)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Downloads\Anaconda3\envs\Python\Lib\ssl.py", line 775, in create_default_context
context.load_default_certs(purpose)
File "C:\Downloads\Anaconda3\envs\Python\Lib\ssl.py", line 596, in load_default_certs
self._load_windows_store_certs(storename, purpose)
File "C:\Downloads\Anaconda3\envs\Python\Lib\ssl.py", line 588, in _load_windows_store_certs
self.load_verify_locations(cadata=certs)
ssl.SSLError: [ASN1] nested asn1 error (_ssl.c:4004)

已尝试操作 #

conda uninstall pyzmq  # (同时会移除jupyter相关包!)
conda install pyzmq  # 重新安装
conda install jupyter  # 重新安装jupyter相关包

该错误是Python的ssl模块加载Windows系统证书存储时，遇到ASN1格式损坏的证书导致，可按以下步骤尝试解决：

• 临时跳过证书验证启动Jupyter
  在命令行执行以下命令，临时禁用证书验证以快速启动Jupyter：

  set PYTHONHTTPSVERIFY=0 && jupyter notebook
  

• 修复Windows系统证书存储

  1. 以管理员身份打开命令提示符，执行证书重建命令：

     certutil -verifyctl rebuild
     

  2. 按下Win+R输入certmgr.msc打开证书管理器，展开「受信任的根证书颁发机构」，检查是否有显示异常的证书（如带红色叉号），右键删除该异常证书。

• 创建全新Conda环境
  当前环境可能存在配置损坏，创建干净环境重新安装Jupyter：

  conda create -n clean_env python=3.9 jupyter -y
  conda activate clean_env
  jupyter notebook
  

内容的提问来源于stack exchange，提问作者AladdinSane90