Parsing value error? What is this?

Configuration
1

2017-07-09 21:02:06 ERROR (MainThread) [homeassistant.helpers.template] Error parsing value: 'None' has no attribute 'Location' (value: null, template: {{value_json.Location.periods[0].Index}})

2

You’ve likely got a value template that’s looking at a variable. The first run - as HA is starting - the value would be null. You can use some if/then logic to avoid this. Or live with the error.