Since the May security update couple of days back I'm facing a strange problem. After the download when I restart the phone the phone gives a 'update failure' message. It gives an option to either 'retry' or 'factory reset' option. Then if I select the 'retry' option, the whole data gets deleted from the phone. Only the apps are reinstalled but I have to sign in to all the apps one by one. Only the data in my SD card is safe.