The Cause:
You’re cruising right along updating everything properly when all of a sudden you get an inexplicable
Could not determine storage version; a valid storage connection or a version hint is required
error
The Cause:
You’ve been upgrading and downgrading Entity Framework Versions. The actual error has nothing to do with the error message listed above.
The Solution:
There really is no good solution to this, as I have spent the past six hours proving – the best thing to do is just to upgrade to Entity Framework 6 and find some other workaround for any other problem.