Mac Care

Moving to a New Mac: A Before, During and After Checklist

A before, during and after checklist for a new Mac: choose Migration Assistant, a Time Machine restore or a clean setup, then erase the old Mac safely.

By Editorial team

Published 10 min read

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A new Mac usually goes wrong in one of three places. Something you needed lived only on the old Mac. An app will not run on the new one because the old one holds its activation. Or the old Mac is wiped before anyone checks the new one.

This guide gives you a checklist for each stage, a decision table for the ways to move data, a table of what does not travel, and a safe order for erasing the old Mac. Steps follow Apple's pages for macOS 27 Golden Gate, the latest release on Apple's macOS version page (27.0.1 since 28 September 2026).

Pick the path: old Mac, Time Machine backup, or clean setup

The first decision is the source of your data, not the tool. Apple's Time Machine restore page also uses Migration Assistant, so the real choice is old Mac or backup as the source (a Windows PC is a third source, below). Per Apple, Migration Assistant moves documents, apps, user accounts, and settings, and neither deletes anything from the old Mac nor replaces macOS on the new one.

Path Choose it when You need Watch for
Old Mac as source The old Mac works and sits beside the new one Both Macs updated, Wi-Fi on, nearby Hours-long transfers; same-name accounts; old clutter
Time Machine backup as source The old Mac is dead, sold, or must stay untouched Backup disk connected and on A backup is only as new as its last run; an encrypted one needs its password
Clean setup, then copy files The old Mac is slow or cluttered, or you want a fresh start Files copied by hand or restored selectively from Time Machine Reinstalling every app; signing in everywhere

Our default: use the old Mac as the source when it works, since it stays unchanged as a fallback.

Before: get the old Mac ready

  • Back up, check the date, and trim. Our Time Machine backup guide covers setup and a restore drill; the Backup Planner sizes a disk from numbers you type. Trimming first shortens the transfer (our reasoning); the storage guide ranks deletion candidates by risk.
  • Update macOS on both Macs (System Settings > General > Software Update); they need not match, Apple says. Its macOS 27 compatibility list names only Apple silicon models, so an Intel-based Mac stays on an earlier macOS.
  • List apps that hold a licence or activation. Note apps with a key, a per-machine activation, or an account. Two documented examples: Apple allows five authorised computers for purchases (Music or TV app, Account menu, Deauthorize This Computer), and Microsoft says Office signs you out of devices automatically within its sign-in limit.
  • Switch on iCloud sync. iCloud Keychain: System Settings > your name > iCloud > Passwords > Sync this Mac. Messages in iCloud: Messages > Settings > iMessage > Enable Messages in iCloud. Both need two-factor authentication.
  • Record the secrets you cannot reset. Your FileVault recovery method, the Time Machine backup password (the backup guide covers both), your Apple Account password, and a trusted device for sign-in approvals. Also take the Homebrew snapshot (commands under After); Apple's migration page does not say how toolchains are treated.
  • Ask IT first on a work or school Mac. Apple documents a separate Managed Migration Assistant that needs macOS 26.4 or later on the new Mac.
  • Pause security software and plug in both Macs. Apple says to turn off antivirus, firewall, and VPN software on either Mac until the transfer ends. Power is our advice.

During: run the transfer

Apple's Migration Assistant article, published 10 February 2026, has one version note: OS X El Capitan or earlier needs a shared Wi-Fi network. In short:

  1. On the new Mac, open Migration Assistant (part of the setup assistant at first start; later in Applications > Utilities or Spotlight). Choose to transfer from a Mac, Time Machine, or startup disk.
  2. On the old Mac, open Migration Assistant, continue, and choose to transfer to another Mac.
  3. On the new Mac, select the old Mac. If a security code appears, check that it matches on both screens.
  4. Wait for the storage calculation, then tick categories, or open one to choose items.
  5. Set passwords. An administrator account asks you to click Set Password (remember it); a standard account gets a temporary one to write down. If an account with the same name exists, replace it (a copy may go to the Deleted Users folder) or rename the incoming one.
  6. Wait: large transfers might need hours and might seem to pause, Apple says. Quit Migration Assistant on both Macs, then log in to the migrated account.

For a Time Machine source, switch on the disk, choose it in step 3, then pick a backup (the arrow beside it shows older ones). If the Mac will not start normally, reinstall macOS first.

From a Windows PC

Apple's PC to Mac page has you download Windows Migration Assistant on the PC: version 3.2.0.0 for Windows 10 or later moving to macOS 27, Tahoe 26, Sequoia 15, or Sonoma 14. On the Mac choose "From a Windows PC", then enter the code it shows into the PC app. Apple's list is data (email, contacts, calendars, media, bookmarks, files), not Windows programs, so reinstall Mac versions.

After: what does not come across, and the fix for each

Apple's pages describe what Migration Assistant moves, not a guarantee that device-bound items survive. Treat this table as an audit.

Item What the sources say Fix on the new Mac
Touch ID fingerprints Apple says fingerprint data is never backed up to iCloud or anywhere else System Settings > Touch ID & Password > Add Fingerprint
Apple Pay cards Each card has a Device Account Number unique to the Mac; signing out removes cards System Settings > Wallet & Apple Pay > Add Card
Passwords iCloud Keychain syncs per device, so it must be on for this Mac Sync this Mac (path above); approve from another device if asked
Messages and Mail History follows Messages in iCloud; SMS reaches a Mac through iPhone forwarding; email may need setting up again Enable Messages in iCloud; iPhone Settings > Messages > Text Message Forwarding; re-add mail
Bluetooth accessories Apple's migration pages do not list pairings System Settings > Bluetooth, point at the device, click Connect
FileVault Apple silicon and T2 Macs encrypt data automatically; the migration pages do not say if the FileVault setting carries over System Settings > Privacy & Security > FileVault; record any new recovery key

Homebrew's FAQ gives the default prefix as /opt/homebrew on Apple silicon and /usr/local on Intel, and its Brewfile documentation calls brew bundle dump a snapshot of installed formulae, casks, and taps. Our reading: copying an Intel prefix brings Intel builds; a fresh install gets native ones. Licences and app sign-ins are the vendor's rule, so sign in again and re-authorise Music and TV.

# Old Mac: write the snapshot (add --force only to overwrite an existing file)
brew bundle dump --file="$HOME/Brewfile.old-mac"

# New Mac, after installing Homebrew from brew.sh: preview, then install
brew bundle check --file="$HOME/Brewfile.old-mac"
brew bundle install --file="$HOME/Brewfile.old-mac"

First-day list:

  • Sign in to your daily apps, work through the table above, and check for Intel-only apps (next section).
  • Review System Settings > General > Login Items & Extensions; our startup items guide explains each kind.
  • Turn security software and VPN back on, and start Time Machine; confirm the first backup finishes.

Intel-only apps and Rosetta after macOS 27

This matters when moving from an Intel-based Mac to Apple silicon. Apple's Intel-based apps page, published 21 September 2026, says Rosetta is "available for any Mac with Apple silicon using macOS 27 or earlier". From macOS 28, the next major release, Rosetta functionality will be available only for certain older, unmaintained games that rely on Intel-based frameworks. The page gives no macOS 28 date. Our reading: outside that exception, Intel-only apps lose translation on macOS 28.

Three checks, per Apple:

  1. Old Mac: select the app in the Finder, choose File > Get Info (Command-I), and read Kind. "Application (Intel)" means ask the vendor for an Apple silicon version.
  2. New Mac on macOS 27: System Settings > General > About, then Details next to Intel-based Apps. Apple says it lists only apps used recently or in common locations.
  3. Rosetta itself: opening an Intel app prompts for the install, or run softwareupdate --install-rosetta in Terminal. Plug-ins and updaters can be Intel-based separately.

Verify the new Mac, then erase the old one

A two-week soak first (our rule)

Apple sets no waiting period. Two weeks is our rule, long enough to hit the weekly and monthly tasks a day-one check misses. Keep the old Mac powered off and its last backup untouched.

  • The new Mac has finished several Time Machine backups, and you restored one real file.
  • Daily apps are signed in and licensed, each Intel-only app has a plan, and printers, displays, Bluetooth gear, Mail, Messages, Wallet, and Touch ID work.
  • Files outside the home folder, and other user accounts on the old Mac, were copied or deliberately dropped.
  • You made one last backup of the old Mac and checked it.

Erase: Apple silicon or T2 Mac on macOS Monterey 12 or later

Warning: Erasing removes every volume and user account, including other people's data, and cannot be undone. Run it only after the soak, with a checked final backup. Unplugging external drives first is our precaution, not an Apple step.

  1. If the Mac has Apple silicon, runs macOS 26 or later, and was repaired (or you are unsure), Apple says to check for an unfinished repair first: System Settings > General > About > Parts & Service. With an AppleCare plan, you can cancel it or transfer it.
  2. Open System Settings > General > Transfer or Reset > Erase All Content and Settings.
  3. Enter your login password, then your Apple Account password when asked, and review the list of items to be removed. Apple's macOS 27 Erase your Mac guide says this signs you out of Apple services and turns off Find My and Activation Lock.
  4. If a message offers to sign you back in, ignore it and click Erase All Content & Settings.
  5. The Mac restarts and ends at the setup assistant. If it is going to someone else, do not continue; hold the power button until it turns off.

Apple's erase article adds that Monterey 12 puts the command in the System Preferences menu, and that a message about other volumes may mean Boot Camp. While Find My is on, Activation Lock requires your Apple Account password before anyone can erase or reactivate the Mac, so a buyer is locked out if Find My stays on. If the old Mac still shows in Find My afterwards, or was offline, sign in at iCloud.com/find, select it, and click Remove.

Older Macs without Apple silicon or a T2 chip

Apple's sell or give away page gives a manual route: sign out of iCloud (System Settings > your name > Sign Out on Ventura 13 or later) and iMessage (Messages > Settings > iMessage > Sign Out), erase the disk in Disk Utility from macOS Recovery, reinstall macOS, and on an Intel Mac reset NVRAM. Press Command-Q at the setup assistant. Signing out of iCloud also turns off Find My.

Where to start this week

  • Today: back up, check the date, and list licences to deactivate.
  • Move day: run the During steps, then the After table.
  • Two weeks later: tick the soak list, erase, and confirm the old Mac has left Find My.

More Mac guides are in the Mac hub.

We build Tend, a free macOS app (macOS 11 or later). Its Resilience Center shows Time Machine freshness and FileVault status read-only, and Background Items review lists legacy startup items. Every step here works without it.

Frequently asked questions

Does Migration Assistant delete anything from my old Mac?

No. Apple says it neither deletes information from the old Mac nor replaces the operating system on the new one, so the old Mac stays a fallback.

Will my Intel apps still run on a new Apple silicon Mac?

Yes, through Rosetta, on macOS 27 or earlier; from macOS 28 Apple limits it to certain older, unmaintained games. Check each app's Kind in Get Info and ask vendors of Intel apps for an Apple silicon version.

Do I need to sign out of iCloud before erasing the old Mac?

Not with Erase All Content and Settings on an Apple silicon or T2 Mac running Monterey 12 or later; Apple says it signs you out and turns off Find My and Activation Lock. Older Macs need manual sign-outs first. If you no longer have the Mac, remove it at iCloud.com/find.

Sources and further reading