相关疑难解决方法(0)

在升级到Django 1.7时,我收到以下错误消息 ./manage.py

$ ./manage.py 
Traceback (most recent call last):
  File "./manage.py", line 16, in <module>
    execute_from_command_line(sys.argv)
  File "/home/johnc/.virtualenvs/myproj-django1.7/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 427, in execute_from_command_line
    utility.execute()
  File "/home/johnc/.virtualenvs/myproj-django1.7/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 391, in execute
    django.setup()
  File "/home/johnc/.virtualenvs/myproj-django1.7/local/lib/python2.7/site-packages/django/__init__.py", line 21, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/home/johnc/.virtualenvs/myproj-django1.7/local/lib/python2.7/site-packages/django/apps/registry.py", line 89, in populate
    "duplicates: %s" % app_config.label)
django.core.exceptions.ImproperlyConfigured: Application labels aren't unique, duplicates: foo

有什么问题,如何解决？