Does Migration Assistant Transfer Everything: The Parts It Skips

The new Mac is on the desk, the old one is still awake next to it, and the question before pressing Continue is a practical one: after this finishes, is there anything left to do by hand. The honest answer is yes, and the useful version of that answer is a list, not a warning. Apple's own description of Migration Assistant is short and precise, and reading it closely tells you most of what will and will not survive the move.

What Apple says it moves, in its own words

Apple's support page for transferring to a new Mac states that Migration Assistant "transfers documents, apps, user accounts, and settings from one Mac to another," and that it "doesn't delete information from your old Mac or replace the operating system (macOS) on your new Mac." That single sentence answers two of the most common fears at once. The old machine is untouched, and the new machine keeps the macOS version it shipped with.

The same page adds a detail that gets skipped in most summaries. Under Learn more, Apple notes that Migration Assistant transfers your email, but that to read it you might first need to set up your email account again in your email app. So even inside the categories Apple lists as transferred, there is a class of item that arrives as data without arriving as a working configuration. That distinction is the whole shape of the problem. Almost nothing is truly lost. A meaningful amount arrives inert.

Before starting, Apple asks for three things: that macOS is up to date on each Mac, that both machines have Wi-Fi on and sit near each other for a wireless transfer, and that antivirus, firewall, or VPN software is turned off on either Mac until the transfer is done. The version numbers do not have to match between the two Macs. That last point matters if the old Mac is several releases behind and you were planning an upgrade first.

The transfer list is a set of checkboxes, not one switch

The step that surprises people is the selection screen. Migration Assistant first calculates how much storage is used by all of your information, including applications, user accounts, files, folders, and settings. Apple's instructions then say to select the checkbox next to each category of files you want to transfer, or to click the disclosure arrow next to a category and select specific items inside it.

That means "everything" is a choice you make, not a default you accept. It also means the answer to the original question depends on what you ticked. A common pattern is to uncheck Applications on the theory that reinstalling is cleaner, then discover that some of the settings you did keep point at apps that are no longer there.

User accounts have their own rules on this screen, and they are worth knowing before you reach them because both involve writing something down.

• Transferring an administrator account: Apple asks you to click Set Password and enter a secure password. This is the password you will use to log in to that account on the new Mac.
• Transferring a standard account: a temporary password is assigned and shown on screen. The user enters it at first login, then sets their own.
• If an account with the same name already exists on the new Mac: you choose between replacing it, with the option to keep a copy of the replaced account's data in the Deleted Users folder, or renaming the old account so both survive as separate logins.

The last case is the one that quietly loses work. If the new Mac was set up with a full account before migration started, and that account shares a short name with the old one, replacing without keeping a copy discards whatever was already there.

Apple also warns that large transfers might need hours to complete and might seem to pause occasionally. A stalled progress bar is not evidence of failure.

Apps arrive, but not all of them arrive working

Applications are in Apple's list of what transfers, and for most Mac software the app bundle really does land in the new Applications folder and open. The gap is everything that lives outside the bundle.

Licences are the first category. Software that ties activation to a machine identifier will treat the new Mac as a new installation, which usually means signing in again and sometimes means releasing a seat on the old machine first. Nothing is lost, but the sequence matters: deactivate on the old Mac before you wipe it, not after.

Permissions are the second. macOS asks per app for screen recording, accessibility, input monitoring, full disk access, microphone and camera. Those grants are attached to the system on the machine that issued them, so a migrated utility may sit there doing nothing until the relevant switch is turned on again in System Settings. Automation tools, window managers, clipboard managers and screenshot tools are the usual suspects.

Architecture is the third, and it now has a deadline attached. Apple states that Rosetta, the translation layer that lets Intel-only apps run on Apple silicon, is available on any Mac with Apple silicon using macOS 27 or earlier, and that from the following major release it will be limited to certain older, unmaintained games that rely on Intel-based frameworks. Apple also notes that on macOS 26.4 or later, launching an app that relies on Rosetta can produce a system notification asking you to update to a native version. If an Intel-only app moved across in a migration years ago and still works today, that is a clock, not a permanent arrangement.

What does not come across at all

Some things are outside Migration Assistant's reach by design, and planning for them is easier than discovering them.

Category	What happens in a Mac to Mac transfer
Documents, photos, music files, folders	Arrive as files, ready to use
Applications	Arrive as apps, but licences and permissions are per machine
Email	Arrives, though the account may need setting up again in the mail app
System and network settings	Arrive, subject to what you ticked
Intel-only apps on Apple silicon	Depend on Rosetta, which Apple is winding down after macOS 27
FileVault recovery keys, external drive encryption	Belong to the old machine and its disks
Browser sessions and signed-in web apps	Depend entirely on the browser, not on Migration Assistant

The Windows route is a useful contrast. Apple publishes a separate table for transferring from a PC, and applications are absent from it. That transfer covers mail, contacts, calendars, tasks, music, podcasts, audiobooks, movies and TV shows, the homepage and bookmarks from Chrome, Edge, Firefox, Internet Explorer and Safari, documents from the home directory, photos, desktop pictures, language and location settings, and known Wi-Fi networks on macOS 13 or later. Windows apps cannot run on macOS, so there is nothing to move. Mac to Mac is the generous case, and even there the app is only half the picture.

When the old Mac is not available

Migration Assistant does not require two live Macs facing each other. Apple's instructions say that when the new Mac asks how you want to transfer your information, you select the option to transfer from a Mac, Time Machine, or startup disk. That opens two alternatives worth knowing about in advance.

A Time Machine backup works as a source in exactly the same way a running Mac does, with the same category checkboxes and the same account-password prompts. This is the route to use when the old machine has already been handed over, has a failed display, or will not hold a charge long enough to sit through a multi-hour transfer. The practical requirement is that the backup is current, which argues for running one final backup before the old Mac leaves the desk.

A startup disk works too, which covers the case of a Mac that no longer boots but whose drive is readable in an enclosure, and the case of a cloned volume made with a disk-copying utility. What it does not cover is a disk whose encryption key you no longer have. FileVault protects the volume, not the account, so an encrypted drive without its password or recovery key is not a migration source.

The choice also affects timing. A transfer from an external disk over a cable is generally faster and less prone to interruption than a wireless transfer between two Macs on a shared network, so when both options exist, the disk is usually the calmer one.

Browser sessions are the quiet gap

For anyone whose working day is spent in web applications rather than native ones, the thing that actually costs an afternoon is not files. It is logins.

A single browser profile holding four Gmail accounts, two Slack workspaces, a project tracker, a billing dashboard and an admin console is a large pile of cookies, tokens and two-factor prompts. Whether that pile survives a migration depends on the browser and its sync account, not on Migration Assistant. Profiles sometimes come over with history and bookmarks intact but sessions expired, which produces the worst version of the outcome: everything looks migrated, and then thirty sign-in screens appear over the following week, each with its own authenticator code.

There is a structural fix, and it is independent of migration. A browser that keeps each web app in its own window and its own cookie container turns that pile into a set of named, separable things instead of one profile you cannot inspect. Tools built around isolated workspaces hold one container per app, so signing into three accounts of the same service at once is normal rather than a conflict, and moving to a new Mac becomes a question of carrying a workspace list rather than reconstructing a browser from memory. The ones that sync that list through your own iCloud or Google Drive, with no vendor account in the middle, are also the ones that survive a machine change with the least ceremony. The wider set of per-app browser features is worth reading before the next hardware change rather than during it.

Preparation that saves a day

None of the following takes long, and each one removes a recovery task from the week after the migration.

1. Note which apps are licence-bound and deactivate the ones that require it on the old Mac while it is still running.
2. Take a screenshot of System Settings, Privacy and Security, for the panes you have customised, so the permission list can be rebuilt quickly.
3. Check whether any app you rely on is Intel-only, given Apple's stated end of general Rosetta support after macOS 27.
4. Export browser bookmarks and passwords deliberately rather than trusting sync, and delete the exported files afterwards.
5. Confirm the new Mac does not already have an account whose short name matches the one arriving, or decide in advance which copy wins.
6. Keep the old Mac intact for two weeks before erasing it. Apple's separate page on what to do before selling or giving away a Mac covers erasing it later.

What to change first

Run the migration, tick every category, and treat the first week on the new Mac as a permissions and licences week rather than a lost-files week. Then fix the part that no migration tool reaches, by moving your web applications out of one shared browser profile and into named per-app spaces with SpaceDeck, so the next machine change costs an hour instead of a weekend.