I'm using the iOS 27 public beta and recently subscribed to iCloud so I could create a full device backup. The backup appeared to upload successfully, but after resetting my phone, the setup process repeatedly fails with "Unable to load iCloud backup." I've tried restoring it around 25–30 times without success. My data is still stored in iCloud, and Apple Support opened a case for me, but there has been no progress after two weeks. I reset the phone while completing a battery replacement, and I'm wondering whether the beta version or the reset process is preventing the backup from being restored.
2 Answers
A backup created while the phone was running a beta generally can’t be restored onto a device running an older iOS version. Make sure the phone is running the same iOS 27 beta build, or set it up as new, install the beta, erase it again from Settings, and then try restoring the backup. Data that was separately synced to iCloud, such as photos or contacts, may still become available even without restoring the full device backup.
Beta backups can be tied to the beta software version, so they may not work with an earlier release or a different build. If the phone is definitely on the beta and the restore still fails, the practical options are to finish setup as new and let your iCloud-synced data download, or wait for a compatible stable release and try the restore again. Avoid erasing the only copy of anything that wasn’t included in iCloud syncing.

The phone is already on the iOS 27 beta, but the backup still fails during setup. I’m hoping there’s another fix because waiting for the stable release would take several more weeks.