安装Angular和React后Django服务器出现ImportError问题求助

原本正常运行的Django服务器，在安装Angular和React后无法启动，抛出如下ImportError错误：

Traceback (most recent call last):
  File "C:\Users\LM\dj\policyboss\manage.py", line 22, in <module>
    main()
  File "C:\Users\LM\dj\policyboss\manage.py", line 13, in main
    raise ImportError(
ImportError: Couldn't import Django. Are you sure it's installed and available on your PYTHONPATH environment variable? Did you forget to activate a virtual environment?

附manage.py代码：

#!/usr/bin/env python
"""Django's command-line utility for administrative tasks."""
import os
import sys


def main():
    """Run administrative tasks."""
    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'policyboss.settings')
    try:
        from django.core.management import execute_from_command_line
    except ImportError as exc:
        raise ImportError(
            "Couldn't import Django. Are you sure it's installed and "
            "available on your PYTHONPATH environment variable? Did you "
            "forget to activate a virtual environment?"
        ) from exc
    execute_from_command_line(sys.argv)


if __name__ == '__main__':
    main()

环境变量截图：

排查步骤 #

• 重新激活虚拟环境：Windows下执行venv\Scripts\activate，Linux/macOS下执行source venv/bin/activate，确保使用安装Django的虚拟环境
• 验证Django安装状态：激活环境后执行pip list，查看输出中是否有Django；若没有，执行pip install django重新安装
• 确认Python解释器路径：执行where python（Windows）或which python（Linux/macOS），检查路径是否和之前运行Django时一致，避免因安装其他工具导致Python版本切换
• 检查PYTHONPATH：执行echo %PYTHONPATH%（Windows）或echo $PYTHONPATH（Linux/macOS），确保项目根目录和虚拟环境的site-packages目录在其中，缺失则手动添加
• 指定解释器安装Django：若存在多Python版本冲突，执行python -m pip install django强制使用当前终端的Python解释器安装Django

内容的提问来源于stack exchange，提问作者aggarwal