ImportError: No module named 'psycopg2._psycopg'

Eureka! I pulled my hair out for 2 days trying to get this to work. Enlightenment came from this SO Question. Simply stated, you probably installed psycopg2 x64 version like I did, not realizing your python version was 32-bit. Unistall your current psycopg2, then:

Download: psycopg2-2.6.1.win32-py3.4-pg9.4.4-release.exe from HERE, then run the following in a Terminal:

C:\path\to\project> easy_install /path/to/psycopg2-2.6.1.win32-py3.4-pg9.4.4-release.exe
C:\path\to\project> python manage.py makemigrations
C:\path\to\project> python manage.py migrate

You may also need to (re)create super user with:

C:\path\to\project> python manage.py createsuperuser

I had the same problem, solved it in this way:

Reinstall the package psycopg2 using pip (by default installed with python 3)

On Linux:

pip uninstall psycopg2

Confirm with (y) and then:

pip install psycopg2

On Windows I add the prefix ('python -m') to the commands above. I think the problem occurs when you change the version of Python. (Even between minor versions such as Python 3.5 and 3.6).