[Answered ]-Django.core.exceptions.ImproperlyConfigured: Application labels aren't unique, duplicates: thumbnail

I went though the same problem of duplicated applications, and following exactly the similar question I solved my problem.

The problem with your solution is that you have added default_app_config = 'sorl-thumbnail.apps.SorlthumbnailConfig' to myproject/mysite/___init____.py, but you should have added to myproject/sorl-thumbnail/___init____.py.