If you owned a defective iPhone 6S and are about to set up a replacement unit with an iCloud backup from your first 6S, you may want to hold off.
iPhone 6S owners voiced their frustrations on Apple’s support forums recently, saying their data from Messages and Recent Calls is missing after restoring their phones from an earlier iCloud backup made with the first iPhone 6S they purchased.
The bug, which was filed on the Apple Bug Reporter on October 3, seems to affect iPhone 6S handsets that updated to iOS 9.0.1 and replacement units running iOS 9.0. Multiple threads in the forum show that the issue is caused when restoring backups from one iPhone 6S to another 6S, but the backup works just fine when restoring from an older device such as the iPhone 6, 5S, 5, or 5C.
While restoring an iPhone 6S backup to a new unit, a brief flash causes the progress bar to disappear and requires the user to do a hard reset. While the dominant problem seems to be the loss of old messages and Recent Calls data, users are also saying the failed backup is causing apps to crash, disrupting Bluetooth connections, missing photos, and losing data from the Health app. Incoming messages are also displaying out of order, and the new iPhone 6S replacements aren’t notifying users when the messages arrive.
A user going by the name of pardthemonster, who first posted about the glitch on the thread, said he does not recommend anyone risk their current phone’s data by performing a backup.
“Thus best candidates would likely be those with a test device, replacement device waiting for the iOS bug fix,” he posted in the thread.
Users in contact with Apple support representatives say the company is aware of the issue and is working on a fix.
iPhone 6S owners left without their original device after getting the replacement are relying on daily local iTunes backups, but one user posted a solution that seems to work if you have access to both phones: Make sure both the new and original iPhone 6S handsets are updated to iOS 9.1, and then run a fresh backup of the original device. Reset the second phone to its factory settings, and then you should be able to restore from the backup on the new device.