Apple has recently been entrapped by i OS 8 screwup up to the hub, from U2-i Tunes invasion to the Health Kit Bug, leading to a swath of complaints from users including i Phone 6/6 Plus users on media and SNS.
Also see: i OS 10 vs i OS 9; How to Upgrade to mac OS Sierra Solution: Getting the error message isn't a big deal as thousands of i Phone i Pad i Pod users around the world are swarming for i OS upgrade.
So you just try it again to deal with the i OS 8 upgrade problem.
Inevitably, there are many problems coming out during i OS 8 update.
To avoid any data loss, you can use the most powerful i OS 8/9/10 data backup software - Mac X Media Trans to effortlessly backup and transfer i Phone i Pad i Pod photos, videos and music to Mac/PC with superfast speed.
Wanna know more information of the upcoming i OS 10 or feel puzzled about i OS 10 update?