This normally only happens if you've ejected the sd card from your device without properly safely removing it from the system beforehand. I suggest you format your sd card, copy everything back over and in future you'll go into settings -> storage sense (also available from the app list of course) -> sd card -> remove sd card.
Ya it happend with me too. just i've connected my mobile to pc via usb and formatted whole sd card and copied the files. from then till now i didn;t get that error again. Hope it may help u too.