I have just started having some trouble with my iPad Air. Shortly after I installed iOS 8.4.1, I noticed the Contacts app was stuck. I CAN open it, but I can't open any of my contact's pages within it, therefore, all the phone numbers, addresses, and notes are lost to me. Tragic! I have closed all other apps, accomplished not one, but two hard reboots, and I've checked to see that Contacts app is still switched ON at Settings > iCloud > Contacts, and it is; none of this made any difference at all. My other apps seem to be working as expected, at least the several dozen I've used since the Contacts app failed. Has anyone else experienced this? I would appreciate any suggestions y'all may have. Thank you.