I have a new iPhone 6. It is replacing an iPhone 5S. I plug this into my iMac every day via an original Apple Lightning cable, and iTunes automatically creates encrypted backups.
I have successfully restored half-a-dozen iPhones in the past from encrypted backups. However, this time the iPhone 6 is requiring all my app and email passwords to be manually re-entered.
Why were my passwords not retained when I restored from the encrypted backup?
Any ideas how I can force a successful restore including passwords?
Possible quirks which may have contributed to this problem:
I had upgraded the 5S to iOS 8.1 before I first tried restoring. The 6 was shipped with an earlier version, so I needed to update to 8.1 before I could attempt to restore my backup to it.
When I tried to restore from a backup the transfer process would hang when transferring apps. I was eventually able to avoid that problem by disabling sync over Wi-Fi first.
(For reasons that leave me completely bamboozled, when I have tried to manually enter email account passwords by copying the passwords stored in my iMac's Keychain, some of them are being rejected. I presume this is simply operator error, but can't work out whether it's a failure to transpose correctly, or a failure to identify the correct password in the first place.)