The error: bad marshal data

When you try to install a python package you get the error:

Traceback (most recent call last): from sqlalchemy.ext.declarative import declarative_base File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/ext/declarative/__init__.py", line 8, in from .api import declarative_base, synonym_for, comparable_using, \ File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/ext/declarative/api.py", line 11, in from ...orm import synonym as _orm_synonym, \ File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/__init__.py", line 17, in from .mapper import ( File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/mapper.py", line 27, in from . import properties ValueError: bad marshal data (unknown type code) if(typeof __ez_fad_position != 'undefined'){__ez_fad_position('div-gpt-ad-tutorials_technology-medrectangle-3-0')}; Solution! =========

Check the traceback path and delete all the pycs files recursively:

find /PATH_ON_TRACEBACK -name '*.pyc' -delete

In our case the path was "/usr", howevery it could be inside your virtualenv.