[Fixed]-RuntimeError: Model class xxx doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS

When it says “Model class xxx doesn’t declare an explicit app_label” your models can specify Meta to define their app_label. You can also customise the database table name along with a bunch of other options as part of the meta data.

You need to do something like this on all your models;

class Author(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    profile_picture = models.ImageField()

    class Meta:
        app_label = 'apfelschuss.votes'

    def __str__(self):
        return self.user.username

edit

I’ve checked out your repo & I think you’re over-complicating the project by having the users and votes apps under apfelschuss.

I pulled them out to the root of the project & everything runs smoothly;
https://github.com/marksweb/apfelschuss/tree/so/questions/55553252

This is a more typical approach to project structure in django/python projects.

I’m using Python 3.7.5 on VS Code. This same issue was confusing me.
I went into the initially created project and found settings.py

Went to the section

INSTALLED_APPS = []

and added

'myapp.apps.MyappConfig', – make sure it’s cased correctly

this refers to the class in apps.py in the app causing issues

You have accidentally added your app name under MIDDLEWARE section in settings.py.

Spent some good time debugging, thought this might help save someone else’s time.

In file apps.py we see:

class ArticlesConfig(AppConfig):
    default_auto_field = 'django.db.models.BigAutoField'
    name = 'Django.apps.articles'

We need name ‘Django.apps.articles’

Now write in terminal:

from Django.apps.articles.models import Article

And all working! I ran into this problem in PyCharm.

I had the same error and fixed it by adding a missing __init__.py file (just a blank file) to my main module inside my project root.

~/my_project
    foo/
        models.py
        tests.py
        __init__.py  # <-- Added an empty __init__.py here