Setting up a second Mac so both feel like the same machine
· 5 min read
A desktop at home and a laptop for elsewhere is a good arrangement until the two drift apart. A file saved on one, a setting changed on the other, an application installed on only one of them, and after a month you are never sure which machine has the current version of anything.
Most of that is preventable by deciding once what syncs and what does not.
What syncs on its own
Sign in to the same Apple Account on both and a surprising amount follows.
Passwords and passkeys, through iCloud Keychain. Turn this on; it removes a whole category of friction.
Safari tabs, bookmarks and history.
Notes, Reminders, Calendar, Contacts, Mail accounts.
Desktop and Documents, if you enable that option in iCloud Drive. This is the big one and it is worth thinking about rather than accepting. It genuinely makes the two machines interchangeable for files. It also means a deletion on one is a deletion everywhere, because sync is not backup. iCloud is not a backup covers that distinction.
Photos, if you use iCloud Photos.
What does not sync, and matters
Applications. Nothing installs software on the second machine for you. App Store purchases can be reinstalled from your account, and everything else you install by hand.
System settings. Trackpad speed, key repeat, Finder preferences, Dock contents, Hot Corners. All per machine. This is the most common source of the two feeling different.
Login items and background helpers. Per machine.
Anything stored outside your home folder. Command-line tools, package managers, virtual machines.
Fonts installed manually.
The pragmatic approach
Rather than trying to make the two identical, decide what actually needs to match.
Make the input feel the same. Key repeat, delay until repeat, tracking speed, tap to click, scroll direction. These are the settings your hands know, and a mismatch is felt immediately. Set them the same on both, first thing. The settings worth changing in the first ten minutes covers what they are.
Make the files the same. Either iCloud Desktop and Documents on both, or a deliberate single location you always work in. What does not work is a vague intention to keep them in step.
Accept that applications will differ. Install what you need on each as you need it. A laptop rarely needs everything a desktop has, and forcing parity creates work.
Keep a short setup note
The genuinely useful habit, and it takes ten minutes.
Write a plain text file listing the applications you install, the settings you always change, and anything with a licence key. Keep it in your synced Documents.
The next time you set up a Mac, whether that is a second machine now or a replacement in three years, that file turns an afternoon into an hour. It is the closest thing to a reproducible setup that does not involve configuration management.
What to keep deliberately different
Not everything should match.
A laptop benefits from more aggressive battery settings, a hidden Dock for screen space, and fewer background applications. A desktop can afford everything.
If you use one machine for work and the other for personal things, keeping browser profiles and accounts separate is a feature rather than a failure of sync. Safari profiles covers doing that within one browser.
Handoff and Continuity
Two machines on the same Apple Account get the features that make them feel like one system: Universal Clipboard, Handoff, AirDrop between them, and unlocking with an Apple Watch.
They need Bluetooth and Wi-Fi on both, and the same account. When they do not work, it is nearly always one of those. Handoff covers diagnosing it.
Back up both
Two Macs need two backups. It is easy to reason that the files are on both machines and therefore safe, and that is not what a backup is: a mistaken deletion syncs to both within seconds.
A backup plan that survives one thing going wrong covers what is reasonable when you have more than one machine.
Questions
Can I clone one Mac to another? Not usefully. Migration Assistant can copy from one to the other during setup, which is the closest equivalent and a reasonable way to start a second machine. After that they diverge.
Should both be signed in to the same Apple Account? Yes, if they are both yours. That is what makes sync and Continuity work.
What about two different macOS versions? Sync works across versions. Some features need both machines reasonably current. Keeping them on the same major version avoids surprises.
Does using two Macs use twice the iCloud storage? No. The storage is your account’s, not per device. The same files sync to both without counting twice.