How to Transfer Data to a New Mac

The short answer. Use Migration Assistant, over a cable if you can, and expect to spend an hour afterwards re-granting permissions rather than copying files. The migration itself is the easy part; the part that catches people is that macOS deliberately does not carry over privacy permissions, kernel extensions or hardware-bound licences, so a machine that looks complete on first boot will still have a handful of apps that do not work until you visit each one.

This guide covers the four routes, what each one leaves behind, and the checklist to run afterwards.

Before you start

Three things, in this order.

Back up the old Mac. Not because Migration Assistant is dangerous — it only reads — but because the old machine is about to be erased, sold or retired, and the migration is the last moment at which its data exists in one place. A Time Machine backup to an external drive is enough, and it doubles as a migration source if the direct route fails. How to back up a Mac to an external drive covers the details.

Update the old Mac to the newest macOS it supports. Migration translates data between versions, and every version gap is another thing that can be mistranslated. Migrating from an older system to a newer one is supported and normal; the reverse is not, and Migration Assistant will refuse.

Write down what is installed and licensed. Open System Settings → General → Login Items and screenshot both lists; open the Applications folder and screenshot it. After migration you will want to compare, because the things that fail to come across are exactly the things you will not notice for a week.

Route 1: Migration Assistant over a cable

This is the fastest and the one to use if both machines are in the same room.

On the old Mac: Applications → Utilities → Migration Assistant, choose To another Mac, authenticate, and note the security code it displays. On the new Mac: run Migration Assistant during Setup Assistant, or later from the same Utilities folder, choose From a Mac, Time Machine backup or Startup disk, then From another Mac, and enter the code shown on the old machine.

Connect the two with a Thunderbolt cable for the fastest transfer, or a USB-C cable if both machines support USB 3 data over it — many USB-C cables are charge-only, so if the machines do not see each other, that is the first thing to check. Wi-Fi works and is dramatically slower: a few hundred gigabytes that takes under an hour over Thunderbolt can take most of a day over 802.11ac.

What it moves: user accounts with their home folders, applications, most preferences, the contents of /Applications, mail, messages, photos, keychains and network settings.

What it does not move, and why:

• System files. Nothing in /System, /usr or the sealed system volume is copied, because the new Mac’s own signed system is what it must run.
• Kernel extensions and system extensions. These are registered with the system and tied to the machine’s security configuration. They have to be reinstalled by their own installers.
• Privacy permissions. Camera, microphone, screen recording, accessibility, full disk access, automation. These are per-machine by design — a copied permission would let malware migrate itself — so every app that needs one asks again.
• Hardware-bound licences. Anything activated against the old machine’s serial number or MAC address needs re-activation.
• Caches. Rebuilt on first launch, which is why the first day feels slow.

Route 2: Migration Assistant from a Time Machine backup

If the old Mac is already gone, or you would rather not have two machines running at once, migrate from a backup instead. Connect the backup drive to the new Mac and choose From a Mac, Time Machine backup or Startup disk.

It is slower than a cable and faster than Wi-Fi, and it has one advantage: it is repeatable. If the first migration produces a machine you do not like, you can erase and run it again from the same source, which is not true of a direct transfer from a machine you have already wiped.

The limitation is age. A backup made under a much older macOS carries settings that no longer mean anything, and Migration Assistant will skip them silently. If the backup is more than two major versions old, expect more reconfiguration afterwards.

Route 3: a clean install and a manual copy

The route nobody recommends and a fair number of people should take: set the new Mac up as new, install only what you actually use, and copy files across by hand.

It is the right choice when the old machine was slow, cluttered or full of software you have been meaning to remove for years — because Migration Assistant is faithful, and it will faithfully bring across every launch agent, every background helper and every preference pane from the last decade. The cost is a day of reinstalling; the benefit is a machine with none of the old machine’s accumulated weight.

The mechanical part is easy. An external SSD is the fastest path: copy the home folder across, then drag back what you need. For a large library, a direct copy with rsync preserves permissions and timestamps better than the Finder:

rsync -avh --progress /Volumes/Old/Users/you/Documents/ ~/Documents/

Cloud storage is the alternative and the slower one, unless the data is already there. If you use Dropbox, Nextcloud or MEGA, the files are already off the machine and the new Mac only has to download them — which makes the transfer a matter of waiting rather than of copying. Arq and Carbonite are the other shape of the same idea: a backup that restores selectively, so you can pull back a folder rather than a machine.

For the file-management side, ForkLift is a dual-pane manager with a queue and verification, which is more reassuring than the Finder when you are copying 400GB and want to know it arrived. Fileside and HandShaker cover the adjacent cases — panes you can arrange, and Android and phone transfers — if the data you are moving is not all on a Mac.

Route 4: iCloud and the account-based route

Worth naming because it is what many people actually rely on, and because it is not a migration.

Photos, Messages, Contacts, Calendars, Notes, Reminders, Safari tabs and iCloud Drive all live in the cloud and appear on a new Mac as soon as you sign in. Nothing needs to be migrated; the new machine downloads what it needs on demand.

What that means in practice: if your data is mostly in those services, “migrating” is signing in and waiting. If your data is mostly in ~/Documents, an external drive or a photo library, it is not. Knowing which of the two you are is worth ten minutes before you start, because it decides whether the migration is a twenty-minute job or an afternoon.

The trap is iCloud Drive’s Optimize Mac Storage, which leaves files as placeholders. A migrated or freshly signed-in Mac may show a full-looking folder that is mostly not downloaded. Selecting the folder and choosing Download Now is the fix, and it takes as long as the data is large.

After the migration: the checklist that matters

The machine boots, the files are there, and about a dozen things do not work. This is normal. Work through it once, methodically.

1. Re-grant privacy permissions. System Settings → Privacy & Security. Camera, Microphone, Screen Recording, Accessibility, Full Disk Access, Files and Folders, Automation. Any app that had one of these on the old Mac needs it again. The ones people forget: backup tools, clipboard managers, window managers, screenshot tools and anything that reads another app’s window.

2. Reinstall the software that installs system components. Kernel extensions, system extensions, privileged helpers, menu bar items that load a login item, VPN clients with a network extension, virtual machine hypervisors. If an app launches and says it needs to install a helper, that is this category — let it.

3. Re-authorise licences. Adobe, Microsoft Office, most pro audio and video software, some developer tools. Have the serial numbers or account logins to hand before you start, because the apps tend to demand them at the least convenient moment.

4. Sign back into the accounts that are not iCloud. Mail accounts re-authenticate; calendar and contacts follow; chat apps re-pair. Two-factor prompts will arrive on whichever device is still signed in, which is a reason not to erase the old machine until the new one is working.

5. Re-pair Bluetooth devices. Keyboards, mice, trackpads, headphones. They may pair automatically if they were signed into the same iCloud account, and they may not; holding the pairing button and re-adding is quick.

6. Check Time Machine. The new Mac does not inherit the old backup history. Point it at a destination and let it make a fresh full backup, which will take hours. Do this before you erase the old machine, so there are two copies rather than none.

7. Verify the things that fail silently. Open the three apps you use most and do one real task in each. Check that Mail can send, that the printer is there, that the VPN connects, that the backup runs. The failures that matter are the ones that do not announce themselves.

The old machine, afterwards

Two paths, and they are not interchangeable.

If you are keeping it, sign out of nothing, but do turn off the services that would otherwise have two machines writing to the same account state. iCloud is designed for this and copes; Time Machine to the same disk does not, and you should give the old machine its own destination or stop its backups.

If you are selling or giving it away, the order matters:

1. Sign out of iCloud, which also removes it from Find My.
2. Sign out of Apple Music, the App Store and Messages.
3. De-authorise any app that counts activations.
4. System Settings → General → Transfer or Reset → Erase All Content and Settings.

That last step is the one that matters for data safety. On Apple Silicon and on T2 Macs it destroys the volume encryption key, which makes the data unrecoverable in a way that overwriting files does not. On older Intel Macs without a T2 chip it is a reformat, and a determined buyer with the right tools could recover something — which is worth knowing if the machine held anything sensitive.

Do not skip the sign-out. An erased Mac still attached to your Apple ID will ask the next owner for your password, and the only way to fix it is to sign in to iCloud on another device and remove the machine from Find My manually.

What actually lives where, and why migration is mostly about one folder

The reason a migration is more than a file copy is that most of what makes a Mac yours is not in your Documents folder.

That table explains both the convenience and the complaint. Migration is faithful to ~/Library, which is why your mail accounts, your app settings and your saved passwords all arrive intact. It is also faithful to ~/Library/LaunchAgents, which is why a five-year-old machine’s accumulated startup items arrive with them.

If you want a middle path between a full migration and a clean install, this is where to intervene: migrate everything, then spend twenty minutes in ~/Library/LaunchAgents and in System Settings → General → Login Items removing what you do not recognise. That is a far smaller job than reinstalling every app, and it captures most of the benefit.

Moving specific things by hand

Some data has a shape that rewards copying directly rather than migrating, either because it is huge, because it must be moved whole, or because it is easy to get wrong.

A Photos library is a package, not a folder, and it must be copied as one unit — dragging the .photoslibrary bundle, not its contents. Merging two libraries is possible with Photos’ own Designate Library and the option to hold Option at launch, but the safe route is to copy the whole thing and open it once.

Mail lives in ~/Library/Mail, in a folder named for the macOS version that wrote it. Copying it into the same path on the new Mac brings the local mailboxes; IMAP accounts re-download from the server anyway, which is why mail is one of the few things where a fresh account setup is genuinely equivalent.

Messages is ~/Library/Messages/chat.db, plus the attachments folder beside it. Copy the pair, and sign in to iMessage afterwards — the history is local, the account is not.

Virtual machines are the largest thing most people forget to account for. A Parallels or VMware bundle can be 60GB, and several of them will not fit in a migration that was planned around documents. Copy them to an external drive and open them from there, or move them after the migration is done.

Developer data is ~/Library/Developer — derived data, archives, simulators, device support files. It is often the single biggest folder in a home directory on a working Mac, and almost none of it needs to travel: derived data rebuilds, simulators can be re-downloaded, and archives only matter if you ship from this machine.

Keychain is worth naming separately because it is the one that catches people out. The login keychain migrates with your account and is protected by your login password, so it unlocks on the new machine as long as the password is the same. If you changed the password during setup, the old keychain will ask for the old one on first use — which is fine, and worth knowing so it does not look like a failure.

Network, printers and the settings that quietly reset

Most network configuration migrates: Wi-Fi networks and their passwords, Ethernet settings, VPN profiles that were configured in System Settings, and the list of known SMB servers.

What does not, or does not reliably:

• Wi-Fi passwords for networks you have not joined recently, which may prompt again on first connection.
• Printers, which usually reappear through AirPrint discovery on the same network but lose their custom settings — paper trays, duplex defaults, presets.
• VPN profiles installed by an app, which come back when the app is reinstalled, not before.
• Firewall rules and content filters, which are per-machine.
• Screen sharing and remote login, which are off by default and must be re-enabled in Sharing.

The practical advice is to write down the printer settings and the VPN endpoints before you migrate, because neither is anywhere you will think to look until you need to print something at 9am.

If the migration will not start

Migration Assistant fails in a small number of predictable ways, and each has a cause worth checking before you resort to a backup.

The machines do not see each other. Both must be on the same network and neither firewall may be blocking the connection. Turn off the firewall on both machines temporarily — System Settings → Network → Firewall — and try again. If you are using a cable, confirm it is a data cable: a charge-only USB-C cable produces exactly this symptom.

It stalls at “Waiting for the other Mac”. Usually the old machine has gone to sleep, or a VPN is routing the local traffic somewhere it should not go. Disconnect the VPN on both machines.

It refuses because of the version. Migrating from a newer macOS to an older one is not supported. Update the new machine first, or migrate from a backup made before the old machine was updated.

The time estimate is nonsense. It is, and it always has been. The first ten minutes are spent scanning and the rate changes repeatedly; judge progress by the disk activity on both machines rather than by the number on screen.

It completes but the new account cannot log in. This happens when the old account name collided with the one created during Setup Assistant. Sign in with the new account, open Users & Groups, and the migrated account will be there as a separate user — you can promote it to admin and delete the temporary one.

FAQ

How long does a migration take? A few hundred gigabytes over Thunderbolt: under an hour. The same over Wi-Fi: most of a day. The migration is followed by hours of first-launch work — Spotlight reindexing, Photo analysis, cloud downloads — during which the machine is slow and warm. Plan for a day, not an hour.

Can I migrate only some users? Yes. Migration Assistant lets you deselect user accounts and choose which applications to bring across. It is a reasonable middle path between a full migration and a clean install: bring your own account and skip the shared one that belonged to a previous owner of the machine.

What if the new Mac has less storage than the old one? Migration Assistant will refuse or truncate. Deselect the largest user accounts and copy their data afterwards from the old machine or a backup, so you can choose what to keep. Photos libraries and virtual machines are the usual reason a migration will not fit.

Do I need the same Apple ID on both machines? No. Migration is machine-to-machine and does not involve the account. The Apple ID matters afterwards, when iCloud and the App Store are signed in on the new Mac.

Is it safe to keep using the old Mac after migrating? Yes, and it is useful to keep it for a week as a reference — it is the only complete copy of the old configuration, including the permissions and licence states you are about to recreate. Erase it once the new machine has been through the checklist, not before.