Comment 1 for bug 960784

I get a similar error with the mongo BSON library:
>>> bson.BSON(s).decode()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/robertc/source/launchpad/oops-datedir2amqp/working/eggs/pymongo-2.1.1-py2.7-linux-x86_64.egg/bson/__init__.py", line 539, in decode
    (document, _) = _bson_to_dict(self, as_class, tz_aware)
UnicodeDecodeError: 'utf8' codec can't decode byte 0x85 in position 5: invalid start byte

I wonder if this is a damaged file and not worth handling (low incident rate, should examine when it happens), or whether its a genuine bug.