Every beta tutorial ever written — including our own iOS 28 install guide — contains a line somewhere near the top that says "back up your iPhone first." Then it moves on to the fun part. This article is the opposite: it stays on that one line for two thousand words, because the backup is the only part of beta testing where a mistake is genuinely permanent. Install problems can be retried. A missing pre-beta backup cannot be created after the fact. With the iOS 28 developer beta projected for June 7, 2027, you have plenty of time to get this right — and a good reason to practice the procedure once this year.
The one-way street: why your iCloud backup won't save you
Most iPhone owners assume they're protected because iCloud Backup runs every night. For normal life, they're right. For beta testing, that assumption fails in a way Apple doesn't advertise loudly: backups only restore forward, never backward. A backup created by a phone running iOS 28 records its data in iOS 28's formats — new database schemas, new settings structures, new fields that iOS 27 has never heard of. When you try to restore that backup onto a phone running iOS 27, the setup assistant simply refuses. It will gray the backup out or tell you a newer version of iOS is required, and there is no override.
Now trace what actually happens to a careless tester. You install the beta on June 7. That night, iCloud does its automatic backup — from iOS 28. The next night, another. Within 24 hours, every recent backup Apple holds for you was made on beta software. If week two brings a bug you can't live with and you decide to go back to iOS 27, you'll wipe the phone, reinstall the stable release, reach the restore screen — and discover that every backup you own is on the wrong side of a door that only opens one way. Your choices at that point are starting from scratch or living with the bug until iOS 28 ships in final form, which we project for mid-September 2027. That's a long time to regret skipping a ten-minute chore.
The only reliable escape hatch is a backup frozen in time from before the upgrade. That's what the rest of this guide builds.
What "archived" means and why it matters
A local backup on your computer solves half the problem — it captures your phone on iOS 27. But there's a second trap: by default, your computer keeps only one current backup per device, and each new backup overwrites the last one. If you make a beautiful pre-beta backup on June 7, then absent-mindedly plug the phone in and sync a week later while running the beta, the new iOS 28 backup replaces the old one. Your lifeboat just got overwritten by the thing you needed a lifeboat from.
Archiving is macOS's answer. When you archive a backup, Finder timestamps it and marks it read-only in its backup catalog. Future backups get written as new entries next to it instead of on top of it. An archived backup sits untouched until you delete it deliberately — which is exactly the behavior you want from an insurance policy.
Step by step on a Mac
- Connect the iPhone with a cable and unlock it. Tap Trust on the phone if prompted.
- Open Finder and click your iPhone in the sidebar under Locations. The General tab shows backup options.
- Choose "Back up all of the data on your iPhone to this Mac" and check "Encrypt local backup." You'll be asked to create a password — more on why this box is mandatory below.
- Click Back Up Now and leave the phone connected. A full first backup of a well-used phone commonly takes 30–90 minutes.
- When it finishes, click Manage Backups. Right-click (or Control-click) the backup you just created and choose Archive. The list will now show it with a date and time stamp, which is your visual confirmation that it's locked.
Step by step on Windows
On a PC, the modern tool is the Apple Devices app from the Microsoft Store (it replaced iTunes for this job). The flow mirrors the Mac almost exactly: connect and unlock the phone, select it in the app's sidebar, pick "Back up all of the data on your iPhone to this PC," enable "Encrypt local backup" with a password, and hit Back Up Now. The one real difference: the Apple Devices app has no Archive button. The Windows workaround is manual but effective — after the backup completes, open the backup folder (see the verification section below), copy the entire dated backup folder somewhere safe, and rename the copy with an obvious label like iOS27-pre-beta-KEEP. A renamed copy can't be overwritten by a future sync, which achieves the same protection archiving does on a Mac.
Why encryption is not optional
The encryption checkbox feels skippable. It is not. An unencrypted backup deliberately excludes the most sensitive — and least replaceable — categories on your phone: Health and Activity data, saved Wi-Fi and website passwords, and call history, among others. Apple omits them from plain backups precisely because they'd otherwise sit readable on your hard drive. Restore from an unencrypted backup and your years of workout history, heart-rate records, and keychain entries simply aren't there. Encrypt the backup and everything comes along. Set the password, then store it in a password manager or write it down somewhere physical — this matters more than it sounds, and we'll come back to it under mistakes.
Verifying it worked (and where it lives)
Don't trust the progress bar; check the receipt. On a Mac, the Finder device screen shows "Last backup to this Mac" with today's date and time, and Manage Backups lists the archive. The raw files live at ~/Library/Application Support/MobileSync/Backup/ — each backup is a folder with a long hexadecimal name, and its modification date should match the backup you just ran. On Windows, Apple Devices stores backups under %USERPROFILE%\Apple\MobileSync\Backup\ (older iTunes installs used a similar path under \Apple Computer\). If the folder is there, dated today, and tens of gigabytes in size, your backup is real.
Disk space: plan before you click
A local backup is roughly the size of the used storage on your phone minus apps themselves (which are re-downloaded on restore, not stored in the backup). In practice that means anywhere from 50 GB for a lightly used phone to 200 GB or more for one loaded with photos and videos stored on-device. Check your Mac's free space first: a backup that dies at 92% for lack of room wastes an hour and protects nothing. If your boot drive can't fit it, know that Apple offers no supported way to change the backup location. The community workaround — moving the MobileSync folder to an external drive and pointing a symbolic link at it — does work and has for years, but it's unsupported, breaks if the drive is disconnected mid-backup, and occasionally survives macOS updates poorly. Use it at your own risk, and only if the alternative is no backup at all.
When to do this
Twice. Do a practice run now, in July 2026 — it costs you nothing, confirms your cable, your disk space, and your encryption password all work, and leaves you an extra safety copy. Then make the real one on the morning of June 7, 2027, before the WWDC keynote, so the archive captures your phone at its freshest possible pre-beta state. Anything you do on the phone after that backup — messages received, photos taken — exists only in the iOS 28 world until the beta period ends. That's the unavoidable cost of the one-way rule, and it's why you take the backup as close to install time as you can. Supported hardware, for planning purposes: we expect iOS 28 to cover the iPhone 13 and newer.
How the restore actually works later
If the beta turns hostile, the path back has two halves. First, the downgrade itself: putting the phone into Recovery Mode, connecting it to your computer, and restoring the current stable iOS — the full walkthrough is in our downgrade guide. That erases the phone completely. Second, the part this article exists for: during setup, the phone reboots into the familiar Hello screen, and when it offers "Restore from Mac or PC," you connect the same computer, select your archived backup from the list, enter your encryption password, and let it rebuild. Because the archive was made on iOS 27, the restore is a legal forward (or same-version) move and proceeds without complaint. Apps re-download from the App Store; Health data, passwords, messages, and settings come back from the archive.
The three mistakes that actually burn people
- Forgetting the encryption password. There is no recovery path — not through Apple, not through your Apple Account. A backup whose password you've lost is a locked safe at the bottom of the ocean. Store the password the moment you set it.
- Backing up after installing the beta. One casual sync on iOS 28 can overwrite an unarchived local backup. Archive on Mac; copy-and-rename on Windows. Then treat that archive as untouchable.
- Assuming iCloud has everything. Beyond the one-way problem, iCloud backups skip data that's already synced (which sounds fine) but leave app-local data at the mercy of each developer's choices. Plenty of apps — games with local saves, some authenticator setups, downloaded media — restore incompletely or not at all. An encrypted local backup is simply more complete.
Do this once, properly, and the beta becomes a low-stakes experiment instead of a leap of faith. For the decision of whether to install at all — and everything else about the beta cycle — start with the full iOS 28 beta guide.