Where iPhone and iPad backups are stored on a Mac

Device backups sit at ~/Library/Application Support/MobileSync/Backup/, one folder per backup, named with a long string of characters rather than the device. They accumulate rather than replace, which is why this folder turns up as the largest single thing on Macs whose owners have never heard of it.

Nothing here counts as System Data or anything else mysterious. It is a plain folder full of files. The only reason it goes unnoticed is the name.

The path

Apple documents one route into it. Open the Go menu in Finder, pick Go to Folder, then give it this.

Inside you will find one folder per backup. The names look like 00008030-001A2C3D4E5F6G7H on newer devices and a plain run of forty hex characters on older ones. Either way it identifies the device rather than describing it, so nothing in the name tells you which iPhone it came from.

Finder shows no route to that folder, since Library stays out of sight. That is also why most of what lives in there goes unexamined.

The route that names the devices

Finder answers the question the folder names cannot.

Connect the device, select it in the Finder sidebar, then click Manage Backups under the General tab. That gives every backup with its device name and its date, which is the pairing you actually need.

Right click any row for Show in Finder, which opens the matching folder. That is how you connect a name to one of those character strings.

You do not need the device to hand. Manage Backups lists everything on the Mac, including backups from phones sold years ago. Those are the ones worth looking at first.

Why it gets so large

Three things compound. None of them announces itself.

Backups are per device. Every iPhone and iPad you have ever connected has its own folder. A household with four devices has four sets.

Old ones are not removed. Replacing a phone does not delete the previous phone's backup. It sits there, complete, for as long as the Mac lasts.

They hold what iCloud does not. A local backup carries far more than a photo library sync, so a single one runs to tens of gigabytes on a well used phone.

Put those together and a Mac that has seen a few upgrades carries several full device images from hardware that left the house years ago.

This is also why the folder shows up in every disk scan posted to a forum. The tool reports a large folder, the name means nothing to the owner, then the thread that follows is somebody being told not to delete it.

Reading what is in there

Two figures decide everything. Manage Backups gives you both.

A backup is safe to remove once the device has gone. It is also safe when the date is old enough that a newer backup supersedes it entirely.

The combination that should stop you is a recent date on a device you still use, because that is the only copy of everything not in iCloud.

Deleting one safely

Use Manage Backups rather than Finder. Select the backup, then delete it from there.

The reason is not fussiness. Apple's guidance on these files is to leave them alone, because a backup is a set of files that reference each other and pulling one out by hand can leave a set that restores partway and then fails. Deleting the whole folder in Finder works. Deleting anything inside one does not. The interface removes the right things without you having to know which.

Where this sits against everything else on the disk is a separate question, answered by reading the storage bar properly before deleting anything.

Encrypted backups behave differently

Worth checking before you delete anything, because the difference is not visible in the folder.

An encrypted local backup carries things an unencrypted one leaves out. Saved passwords, Wi Fi settings, Health data and call history all travel only in an encrypted backup. The unencrypted version of the same device is a smaller and less complete thing.

So a Mac holding both for one device is holding two backups that are not interchangeable. The larger one is probably the encrypted one. That is the one worth keeping.

Manage Backups marks the encrypted ones with a padlock. If you no longer know the password for one, it cannot be restored by anybody, which makes it dead weight rather than a safety net.

Moving them to an external drive

This comes up constantly and deserves a straight answer.

Finder offers no setting for it. There is no preference, no menu item and nothing in System Settings. What circulates instead is a Terminal recipe that copies the folder to an external drive and leaves a link behind so Finder still finds it at the old path.

It works. It is also unsupported, with a failure mode people meet later rather than sooner. The link points at a volume that has to be mounted. Back up with the drive unplugged and macOS finds nothing at the path, so it creates a fresh backup on the internal disk and the space you saved comes straight back.

Two calmer options exist. Copy the whole Backup folder to an external drive as an archive, then delete the originals and let the Mac make new ones. Or accept that recent backups live on the Mac and remove the old ones instead.

This is not your iCloud backup

The two get conflated and they are separate things.

An iCloud backup lives on Apple's servers, counts against your iCloud storage and takes no room on the Mac. A local backup lives in the folder above, counts against your disk and is invisible to iCloud.

Having one does not remove the other. A phone backing up to iCloud nightly can still have a three year old local backup sitting on a Mac, taking 60GB, because somebody plugged it in once.

That combination is the usual explanation for a folder nobody remembers creating.

The short version

One path, with Library hidden, so paste it. Manage Backups in Finder to see which device each folder belongs to and when it was made. Delete from there rather than by hand, oldest first, keeping the newest for anything you still own.

The rule underneath all of it is simple enough. A backup of a device you still use is not spare space. Everything else in that folder probably is.