I have 2 iPad mini retina's that can turn guided access on just fine but if you reset the iPad (holding down power and home for 10 seconds) when they come back up they are no longer locked to the app that I locked it to. My son has figured out that even if I lock it on ibooks for reading, he can reset without knowing the password and when it reboots it is no longer locked. I have tested this several times on both ipad mini's and I can lock them with guided access and unlock them successfully but if I lock them and then force reset the ipad holding down power and home for 10 seconds then it exits when it comes back up.
I just backed up one ipad and restored to factory settings and guided access works fine and stays locked even if I hard reset. Not wanting to erase and restart with all of the data on this thing I tried reset all settings, reset network settings, reset keyboard dictionary, reset home screen layout and reset location & privacy. None of it worked.
The ipad is working at factory defaults so I restored from itunes backup but despite a full itunes backup, half of the apps were missing and all the ibooks. So I erased and restored from iCloud and then received a message some items could not be restored. So I erased and tried again but this time I restored from icloud instead of itunes and everything restored, including my own epub books I had added to the ipad via Calibre. I turned on guided access and forced restarted the ipad and it worked! I tried it a few more times and it stopped working again.
There is a setting somewhere messing this up or iOS 8.1 still has bugs with this.
If you want this to work I suggest you restore to factory defaults and start from scratch without doing any type of restore.
If you must do a restore I suggest using icloud, backing up the device fully via icloud, then erase all settings and content and restore from icloud. If you get the message that some items could not be restored then erase it again and restore again. You may still get the message some items could not be restored if you have any apps that are no longer available on the app store. Always best to wait for the restore to finish before attempting to open ibooks or any apps that are still restoring data.
Hoping Apple fixes this in the next update.
Dennis
