That message is probably coming from the PHD2 guiding software. PHD2 wants the scope to be pointing near the meridian and the celestial equator when it does a calibration. If you haven't checked the box that says to reuse the existing calibration, the software will perform a fresh calibration when you start guiding. Maybe the checkbox got cleared when the update happened?
Or, it's something completely different, but I'd suggest checking that setting first.