The short version: export your configuration from Rectangle‘s settings on the old Mac, install the app on the new one, grant Accessibility access, then import the file. The permission is the part people miss, because it’s the one thing that never travels with your settings no matter how you migrate.
Settings move, permission doesn’t
Two separate things live on your old Mac: a preferences file holding every shortcut and option you configured, and an Accessibility grant that tells macOS this app may control other applications.
The first is portable. The second is bound to the machine that issued it, by design, since a permission that could be copied between computers would be a poor security boundary.
Which produces the situation that brings most people to this page. Migration Assistant moved everything faithfully, Rectangle is in Applications, its settings window shows all your custom shortcuts exactly as you left them, and pressing one does nothing. Nothing is broken and nothing needs repairing. The app simply hasn’t been given permission on this machine yet.
The migration, in order
Before you wipe the old Mac
Open Rectangle’s settings and export your configuration to a file. Put it somewhere you’ll actually find it later: iCloud Drive, a USB stick, wherever your other migration files are going. This takes about twenty seconds and is the whole reason the rest of the process is easy.
If the old machine is already gone or wiped, skip ahead to rebuilding from defaults. It’s less painful than it sounds.
On the new Mac
Install Rectangle from the official site or with Homebrew, then launch it once. It’ll prompt for Accessibility access on first launch, so approve that now rather than dismissing the dialog and returning to it later. The app can’t do anything until you do.
Then open settings and import the file you exported. Your shortcuts and options come back in one step. If the imported shortcuts don’t respond immediately, quit Rectangle from the menu bar and open it again; the configuration loads on launch and a restart settles it.
If Migration Assistant already ran
You probably don’t need the export at all. Check whether your custom shortcuts are present in Rectangle’s settings on the new Mac. If they are, the preferences file came across, and the only thing missing is the Accessibility grant, which lives in System Settings → Privacy & Security → Accessibility.
If Rectangle is already listed there with its toggle on and still does nothing, that’s a stale permission record rather than a missing one, and the fix is to remove the entry with the minus button and add it back. Same repair as after a macOS update, for the same underlying reason.
What doesn’t survive a change of screen
One part of a migration is worth checking rather than assuming.
Halves, thirds, quarters and every other proportional command adapt to whatever display they land on, so those transfer perfectly. A left half is a left half on a 13-inch laptop and on a 49-inch ultrawide.
Custom sizes defined in pixels don’t work that way. A window position tuned for a 3440-wide monitor makes no sense on a laptop panel, and if you moved from a desktop setup to a laptop, or the reverse, those specific entries need revisiting. This mostly affects Rectangle Pro users, since pixel-exact custom positions are a Pro feature, but it’s the one part of a config that a migration can’t sensibly translate for you.
Rebuilding without an export
No backup, old Mac already gone. This is more common than the tidy version, and it’s fine.
Install Rectangle, grant Accessibility, and use it with the defaults for a week. The defaults are good, and they’re what most people run permanently. As you hit the two or three places where your old configuration differed, change those and only those.
What you’ll find is that you had a handful of meaningful customizations and a long tail of settings you changed once and never thought about again. Rebuilding surfaces which is which. Export the result this time.
Keeping several Macs in step
If you’re not migrating so much as running a work machine and a personal machine, exporting and importing after every change gets tedious quickly, and in practice it means the two configurations drift apart.
Rectangle Pro syncs settings through iCloud, so a shortcut you change on one Mac appears on the other. Worth knowing that a settings reset propagates the same way, which catches people out: resetting to defaults on the laptop can push defaults to the desktop too.
On the free version, the practical habit is exporting after any significant reconfiguration and keeping the file in iCloud Drive. Not automatic, but it takes twenty seconds and it means a new Mac is never a rebuild from scratch.
Frequently asked questions
Whether you’re using Rectangle for Mac to manage windows or restore settings after a migration, understanding the Accessibility permission is key. If you haven’t tried Rectangle yet, it’s a free tool that makes window management effortless.
Does Migration Assistant carry Rectangle settings across?
It usually carries the application and its preferences file, so shortcuts often survive. It never carries the Accessibility permission, which is tied to the individual machine. That’s why Rectangle frequently appears installed and configured on a new Mac while doing nothing at all.
Why does Rectangle do nothing on my new Mac even though the shortcuts are all there?
Because settings and permission are separate things. Your configuration transferred, the Accessibility grant didn’t, and without it the app can’t move windows belonging to other applications. Approving Accessibility in System Settings resolves it.
Can I copy the preferences file directly instead of exporting?
You can, and it works when both machines run comparable versions of the app. The export option is safer because it’s designed for this purpose and less likely to break across versions. Copy the file manually only when the old Mac is no longer available to export from.
Will my layouts still fit on a different sized screen?
Proportional commands like halves and thirds adapt to any display, so those transfer cleanly. Custom sizes defined in pixels don’t, and a layout built for a large external monitor will look wrong on a laptop panel until those specific entries are adjusted.