Flask: No user_loader has been installed for this LoginManager

[Larz60+]

So, the error may have been there for a while.
Try this, (if you don't have git installed, you will have to install it: https://git-scm.com/book/en/v2/Getting-S...alling-Git )
this is seat of the pants, so may need some adjustment, and you're on windows and I on Linux

• open a terminal (or 'command window' if on windows)
  
• change to directory where you want to create new microblog (obviously can't already be a microblog there)
  
• type: git clone https://github.com/miguelgrinberg/microblog
  
• cd microblog
  
• type: python -m venv venv
  
• Create a requirements.txt file from your current tutorial environment:
  • (activate venv on old tutorial)
    
  • type pip freeze > requirements.txt
    
  • type: deactivate
    
  • move requirements.txt to new microblog directory
    
• activate new virtual environment
  
• upgrade pip: pip install --upgrade pip
  
• load packages: pip install -r requirements.txt
  
• get chapter 7: git checkout v.07
  
• if you get error: Please commit your changes or stash them before you switch branches.
  then type: git stash and then git checkout v.07
  
• Try running new flask
  

if this works, your code should be good through chapter 7 if you want chapter 6 instead, use git checkout v.06