If you've opened Storage settings or run a disk-space audit and spotted a folder eating several gigabytes — or even tens of gigabytes — you've probably landed here asking about the MobileSync folder on Mac. It's one of the less-obvious storage drains on macOS Sequoia and Tahoe, and it confuses a lot of people because Apple doesn't surface it prominently in System Settings. This guide explains exactly what it is, where it lives, how large it can get, and the safe way to trim or remove it without losing anything you need.
What Is the MobileSync Folder?
MobileSync is the folder macOS uses to store local backups of your iPhone and iPad when you sync via Finder (macOS Catalina and later) or, historically, via iTunes. Every time you plug in your device and click Back Up Now, or when a wireless backup runs automatically, a snapshot of your device is written here. The backups are incremental — only changed files are added on each run — but over time, if you own multiple devices or keep old backups around, the folder balloons quickly.
It also stores media synced from iOS devices in older workflows, but in practice the bulk of the size almost always comes from device backups.
Where Is the MobileSync Folder on Mac?
The canonical path is inside your user Library, which is hidden by default:
~/Library/Application Support/MobileSync/Backup/You can open it directly from Finder: hold Option, click the Go menu, choose Library, then navigate to Application Support > MobileSync > Backup. Alternatively, paste the path into Finder's Go > Go to Folder dialog.
Inside Backup/ you'll find one or more subdirectories with long alphanumeric names — one per backed-up device. Each of those folders contains thousands of small files organized in a flat hash-based structure, which is why they look cryptic but are perfectly normal.
How Much Space Does It Use?
Size varies enormously based on how many devices you've backed up to this Mac and how full those devices are. Below is a representative breakdown:
| Scenario | Typical MobileSync Size | Notes |
|---|---|---|
| One iPhone (128 GB, ~60 GB used), recent backup only | 10–25 GB | Most common single-device footprint |
| One iPhone with multiple old backups retained | 30–60 GB | Old backups are never auto-deleted |
| iPhone + iPad, current backups | 20–50 GB | Each device gets its own subfolder |
| Power user: multiple devices + years of backups | 80–200+ GB | Easily the largest hidden folder on the Mac |
| iCloud Backup enabled, never synced locally | 0 bytes (folder may not exist) | Local backups only happen if you manually trigger them in Finder |
To check your actual size right now, open Terminal and run:
du -sh ~/Library/Application\ Support/MobileSync/Backup/Is It Safe to Delete the MobileSync Folder?
Yes — with one important caveat: deleting a backup means you can no longer restore your device to that point in time from your Mac. Before you delete anything, confirm that either (a) you have a current iCloud Backup for your device, or (b) you don't need to restore to a previous state.
The MobileSync folder itself does not affect day-to-day device operation. Your iPhone or iPad continues working normally whether or not a local backup exists. Deleting old or stale backups carries no risk beyond losing the ability to roll back to that snapshot.
How to Safely Delete iPhone Backups on Mac (Step-by-Step)
The recommended way is through Finder or System Settings — not by manually deleting files — so macOS can track the removal cleanly.
- Connect your iPhone or iPad via USB, or leave it disconnected if you're managing backups for a device you no longer own.
- Open Finder and select your device in the sidebar under Locations. (If the device isn't connected, skip to step 4.)
- Click Manage Backups… in the General tab. A list of all local backups appears, with the device name, date, and size for each.
- Right-click any backup you want to remove and choose Delete Backup. Confirm when prompted.
- Alternatively, go to System Settings > General > Storage, scroll down to find iPhone/iPad backups (on macOS Sequoia this appears under the storage breakdown), and delete from there.
- After deletion, re-run the
ducommand above to confirm the space was reclaimed.
If you want to delete the entire Backup/ folder manually (for example, to wipe backups for devices you no longer own that don't appear in Finder), you can do so safely:
rm -rf ~/Library/Application\ Support/MobileSync/Backup/macOS will recreate the folder the next time a backup runs. This is one of the few Library subfolders where manual deletion is straightforward — unlike caches, where the wrong deletion can corrupt app state. To understand how these storage categories differ, see our guide on what counts as System Data in Mac storage.
MobileSync vs. iCloud Backup: What's the Difference?
Local Backups (MobileSync)
- Stored on your Mac at
~/Library/Application Support/MobileSync/Backup/ - Created when you click Back Up Now in Finder or enable Wi-Fi sync
- Full backups available offline; fast restore without an internet connection
- Not deleted automatically — they accumulate until you remove them
- Encrypted if you check Encrypt local backup in Finder (strongly recommended to preserve Health and password data)
iCloud Backups
- Stored in Apple's cloud; not on your Mac at all
- Run automatically when your device is locked, on Wi-Fi, and charging
- Subject to your iCloud storage quota (5 GB free tier fills up fast)
- Apple retains the last backup per device; older ones are purged after 180 days of inactivity
Most users benefit from having both: iCloud for automatic daily coverage, and an occasional local backup before a major iOS update. But if you rely entirely on iCloud, you can safely clear the MobileSync folder entirely.
Other Large Folders to Check While You're Here
Once you've dealt with MobileSync, a few neighboring directories are worth inspecting. They aren't always large, but on developer machines or devices with long histories they frequently are:
~/Library/Developer/Xcode/DerivedData/— Xcode build artifacts, often 10–50 GB on active dev machines~/Library/Caches/— app caches that are generally safe to clear (see our explainer on Mac cache files)~/Library/Application Support/— app data; varies widely; some folders are safe to remove for apps you've uninstalled~/.Trash/— if you haven't emptied the Trash recently, it might hold gigabytes of deleted files~/Movies/— screen recordings and Final Cut Pro libraries land here by default
A tool like Crumb can audit all of these folders at once and show you what's safe to remove before you delete anything, which is especially useful when you're not sure whether a particular subfolder belongs to an app you still use.
Keeping MobileSync Under Control Going Forward
A few habits that prevent MobileSync from silently growing back to an unmanageable size:
- Delete old device backups promptly. When you upgrade to a new iPhone, delete the old device's backup after confirming the new phone is set up correctly.
- Pick one backup strategy. If you rely on iCloud Backup, disable local backups: in Finder, select the device, and uncheck Back up all of the data on your iPhone to this Mac.
- Set a reminder after iOS updates. It's easy to create a local backup before a major update and forget to clean it up once the update succeeds.
- Check size quarterly. Add the
ducommand above to your maintenance rotation, or use a disk-space visualizer to catch growth early.
The MobileSync folder is one of those corners of macOS that quietly accumulates data for years without any warning. Understanding what it holds — and knowing the safe, Apple-sanctioned path to clear it — puts you in control of your disk space without any risk to your devices.