That old iPhone backup is quietly hogging 50 GB of your Mac

Updated September 2026 · 5 min read

Every time you back up an iPhone or iPad to your Mac, macOS stores the entire snapshot locally. These backups don't clean themselves up. They just sit there — 5, 20, sometimes 50 GB each — long after you've sold that phone or switched to iCloud backup. If your Mac is running low on space, old iOS backups are one of the first places to look.

Where your Mac stores iOS backups

All local iPhone and iPad backups live in a single folder:

~/Library/Application Support/MobileSync/Backup

Inside you'll find subfolders with long hex names — one per backup. There's no obvious label telling you which folder belongs to which device, which is why most people never check here. The entire MobileSync folder can easily be 20–100 GB on a Mac that has backed up more than one device over the years.

How to see your backups (and which device they belong to)

The easiest way is through Finder:

Open Finder and click your Mac's name in the sidebar (or go to System Settings → General → Storage and look for iOS Files).
Connect your iPhone or iPad via cable. In the sidebar, click the device name.
Click Manage Backups. You'll see a list of all local backups with the device name, date, and size.

If you don't have the device anymore, you can still see the backups here — they'll show the device name as it was when the backup was created. A backup from "John's iPhone 12" will still carry that label even if you sold that phone two years ago.

How to tell if a backup is safe to delete

Ask yourself two questions:

Do I still own this device? If you sold it, traded it in, or gave it away, the backup is useless — the new owner wiped it during setup.
Is iCloud Backup turned on? If your current iPhone backs up to iCloud automatically (check Settings → [your name] → iCloud → iCloud Backup on the phone), the local Mac copy is redundant.

If either answer is yes, the backup is a candidate for deletion.

How to delete old backups

Method 1: Through Finder (recommended)

Open Finder, connect any iOS device (or go to System Settings → General → Storage → iOS Files).
Click Manage Backups.
Right-click the backup you want to remove and choose Delete Backup.
Confirm the deletion.

This is the safest method because macOS handles the cleanup properly.

Method 2: Navigate manually

Open Finder and press Cmd + Shift + G, then paste:

~/Library/Application Support/MobileSync/Backup

You'll see folders with hex names. To identify which folder belongs to which device, open the small Info.plist file inside each one — it lists the device name and last backup date. Once you've confirmed which folder is the old backup, move it to Trash and empty Trash.

What happens when you delete a local backup

Only the copy on your Mac is removed. Nothing changes on your iPhone or iPad — your photos, messages, apps, and settings all stay on the device. If you have iCloud Backup enabled, your cloud backup is also unaffected.

The only thing you lose is the ability to restore that specific device to that specific point in time from your Mac. For a phone you no longer own, that ability was already worthless.

When NOT to delete: if the backup is your only copy of important data — photos that aren't in iCloud, text messages you need to keep, Health data — do not delete it until you've confirmed you have another copy. If you're unsure, plug in your current device and create a fresh backup first, then delete the old one.

How to stop backups from piling up again

Switch to iCloud Backup. On your iPhone, go to Settings → [your name] → iCloud → iCloud Backup and turn it on. Your phone will back up overnight when it's on Wi-Fi and charging.
Check after upgrading. When you set up a new iPhone from a local backup, the old backup stays behind. Get in the habit of deleting the previous device's backup once you're sure the new one is working.

If your Mac is still tight on space after clearing old backups, there's usually more to reclaim in caches, downloads, and system leftovers. See our full guide on how to free up space on Mac for the complete list, or start with finding what's actually taking up your storage.

Let Gigatidy find the backups you forgot about

Gigatidy scans your Mac locally, spots old iOS backups (and everything else eating your disk), and explains what's safe to remove — before you delete anything. Coming soon to the Mac App Store.

Meet Gigatidy →

FAQ

Will deleting an iPhone backup from my Mac erase anything on my phone?

No. The backup is just a copy stored on your Mac. Your iPhone's data — photos, messages, apps, settings — stays exactly as it is. If you also have iCloud Backup on, that cloud copy is completely separate and unaffected.

How big are iPhone backups on Mac?

Typically 5–50 GB each, depending on how much data was on the device. A phone with lots of photos and apps will produce a larger backup. If you've backed up multiple devices over the years, the combined total can easily reach 100 GB or more.

Can I move iPhone backups to an external drive instead of deleting them?

You can copy the backup folder to an external drive manually before deleting it from your Mac. Just navigate to ~/Library/Application Support/MobileSync/Backup, copy the folder you want to keep, paste it to your external drive, then delete the original. Keep in mind you won't be able to restore from it directly — you'd need to copy it back first.