Openweathermap sensor fails after migrated from pi1 to pi3


I just migrated my existing HA from a Raspberry Pi B+ to Raspberry Pi3.
The original one was installed some months ago following the installation guide in a virtual env on a fresh Raspbian Jessie.
Then, recently, I wanted to switch to a PI3. So I installed it the same way except for the system which is now a Raspbian Stretch.
Finally, I copied .homeassistant directory with all the .yaml files from one system to the other.

Openweather map is working as expected on the PI1 but fails to start on the PI3.
One of the difference I noticed is Python release. On the PI1 it’s a 3.4.2 while on the Pi3 it’s 3.5.3.
My current HA release is 57.2

Here is an extract of my sensors.yaml:

- platform: openweathermap
  api_key: my_api_key
  forecast: 1
  name: Météo
    - temperature
    - rain
    - snow

It’s working fine on the PI1 but not the PI3. Here is what I get:

Traceback (most recent call last):
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/helpers/", line 170, in _async_setup_platform
    SLOW_SETUP_MAX_WAIT, loop=self.hass.loop)
  File "/usr/lib/python3.5/asyncio/", line 400, in wait_for
    return fut.result()
  File "/usr/lib/python3.5/asyncio/", line 293, in result
    raise self._exception
  File "/usr/lib/python3.5/concurrent/futures/", line 55, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/sensor/", line 70, in setup_platform
    owm = OWM(API_key=config.get(CONF_API_KEY), language=language)
  File "/srv/homeassistant/lib/python3.5/site-packages/pyowm/", line 49, in OWM
    cfg_module = __import__(config_module,  fromlist=[''])
  File "/srv/homeassistant/lib/python3.5/site-packages/pyowm/webapi25/", line 2, in <module>
    from pyowm.webapi25 import observationparser, observationlistparser, \
  File "/srv/homeassistant/lib/python3.5/site-packages/pyowm/webapi25/", line 8, in <module>
    from pyowm.webapi25 import observation
ImportError: cannot import name 'observation'

Did not find any suitable solution.

Well I found my sdcard is dying. I got some random and weird file system errors.
I reinstalled on a good one and problem disappeared.