Should you migrate or start clean on a new Mac?
· 6 min read
The choice arrives in the first five minutes of a new Mac and is awkward to reverse. Migrate, and the new machine is immediately yours, along with everything that accumulated on the old one. Start clean, and you get a machine with nothing on it you did not choose, at the cost of an evening.
Neither is right in general. The question that decides it is narrower than people expect.
The question that actually decides it
Was the old Mac behaving well?
If it was fast, stable and predictable, migrate. Whatever is on it is not causing trouble, and reproducing your setup by hand is hours of work for no benefit.
If it was slow, crashed, showed odd permission prompts, or had problems nobody diagnosed, start clean. Migration copies the cause along with everything else, and there is a particular disappointment in unboxing a new Mac and finding the old machine’s problem waiting on it.
That single question resolves most cases. The rest of this is for when it does not.
What Migration Assistant actually brings
More than people assume. Applications, your home folder, system settings, user accounts, printers, network settings and keychain items.
That is genuinely convenient and it is also the point people underestimate: it brings login items, background helpers, leftover preference files from software removed years ago, and configuration you have long forgotten setting. None of it is visible, and all of it is now on the new machine.
For a Mac that has been migrated three or four times already, the accumulated layer can be a decade old. It usually causes nothing worse than clutter. Occasionally it is exactly why the old machine misbehaved.
What a clean start actually costs
Honest accounting, because it is usually underestimated too.
Reinstalling applications takes an evening, and finding licence keys for the ones you bought outside the App Store can take longer. Transferring apps when you have lost the licences covers digging those out before you need them.
Reconstructing settings is the part that stretches. Not the big ones, which take minutes, but the hundred small adjustments you made over years and no longer remember making. You will notice them one at a time over a fortnight.
And you still have to move your files, which means an external drive or a network copy rather than the guided process.
The middle path
Most people are better served by neither extreme.
Migrate your files and nothing else. Migration Assistant lets you choose what comes across, with separate checkboxes for Applications, Users, Settings and Other files. Select your user account’s documents and deselect Applications and Settings.
You get your files without the accumulated configuration, and you reinstall applications deliberately, which is the part worth doing by hand anyway. The evening becomes an hour.
Or migrate fully, then prune. Bring everything, then spend twenty minutes on the login items and background helpers. System Settings, General, Login Items shows both lists, and it is usually the first place a decade of accumulation shows up.
Timing, which people get wrong
Whichever you choose, two practical notes.
Do it when you do not need either machine. A full migration over a cable takes about an hour for a modest amount of data and considerably longer over Wi-Fi. Starting it at the end of a working day, on a laptop at nine percent, is how migrations get interrupted halfway.
Update the new Mac first, before migrating. New machines often ship with an older macOS, and migrating into an old version then updating is more disruptive than the reverse.
Back up the old Mac first, either way
This is not optional and it is regularly skipped.
Migration reads from the old machine. It does not modify it, and things do go wrong: cables come loose, machines sleep, processes hang. A current backup means an interrupted migration is an inconvenience rather than an event.
If you have no backup, make one before you start. A backup plan that survives one thing going wrong covers what a reasonable arrangement looks like, and backing up before a major upgrade applies equally here.
Keep the old Mac intact for a fortnight
Do not erase it the same week. Two weeks of ordinary use will surface the handful of things that did not come across, and having the old machine available turns each into a two-minute retrieval rather than a problem.
When you are confident, erase it properly. Erasing a Mac before you sell or hand it on covers doing that so the next owner gets a usable machine and none of your data.
Questions
Can I migrate later, after setting up? Yes. Migration Assistant is in the Utilities folder and runs any time. It is slightly messier than doing it during setup, because you already have an account, but it works.
Does migrating bring viruses across? Malware on a Mac is uncommon, and migration would carry it if present. The more realistic concern is misconfiguration and clutter rather than infection.
Will my applications need reactivating? Some will. Applications tied to hardware identifiers frequently ask you to authorise the new machine, and a few require deauthorising the old one first. Worth doing before the old Mac is erased.
I am moving from an Intel Mac to Apple silicon. Does that change things? Migration works across the transition. Some older applications may not run natively and will need updating. That is an argument for reinstalling applications rather than migrating them, so you get current versions.