MacDisplay 3.0: your second Mac can now do much more

You can transfer files directly between them, move your keyboard and mouse from one Mac to the other, and, whenever you need to, keep MacDisplay completely off Wi-Fi and running over the cable only.

The core of MacDisplay hasn't changed. You can still use an iMac, MacBook or another compatible Mac as an extended display for your main Mac. What's new is everything that can now happen over that same Mac-to-Mac connection.

Mac-to-Mac file transfer over the cable

The first major addition in MacDisplay 3.0 is direct file transfer between Macs.

If your computers are already connected over Thunderbolt or Ethernet, you can simply drag files into the MacDisplay transfer window and send them straight to the other Mac. There's also a drop area you can keep on your Desktop: drag a file onto it and the transfer begins.

There's no need to prepare a USB drive, upload the file somewhere first, or interrupt what you're doing. File transfer uses the same physical connection that MacDisplay can already use for your second display.

The feature is deliberately cable-only. Transfers run over Thunderbolt or Ethernet, so the files move directly between the two Macs. Actual speed depends on the connection and, particularly on newer machines, on how quickly the SSDs in both Macs can read and write the data.

If several Macs are available on the same wired connection, a Send to menu lets you choose exactly where the files should go.

One keyboard and mouse across two Macs

The second major addition changes the way you can work with the other Mac.

With MacDisplay 3.0, move the pointer beyond the edge of your screen and it continues directly onto the other computer. Your keyboard follows with it, allowing you to work across two separate Macs using the same mouse, trackpad and keyboard.

This is different from extending your display. When you use MacDisplay as a second monitor, you're expanding the desktop of your main Mac. With Keyboard & Mouse, you're controlling the other Mac itself, including its own desktop, apps and files.

Clipboard sharing is optional as well. You can copy something on one Mac and paste it on the other without changing the way you work.

The connection is protected with end-to-end AES-256-GCM encryption. The first time two Macs connect, both screens display a six-digit code. Check that the numbers match and approve the connection.

Whenever you want to bring control immediately back to the Mac in front of you, press ⌃⌥⌘.

Keyboard and mouse control works over the cable connection and can also use Wi-Fi when needed. Wi-Fi will be slower, while using the same encrypted connection.

Lockdown mode: keep MacDisplay off public Wi-Fi

The new Lockdown mode is designed especially for situations where your Mac is connected to a public, shared or otherwise untrusted Wi-Fi network.

That might be a hotel, university, coworking space, airport, shared office or any other place where you're using a network you don't control.

Turn on Lockdown and MacDisplay will completely exclude Wi-Fi from its own connections, regardless of which wireless network your Mac is currently using.

From that point on, display extension, file transfer, and keyboard and mouse control will run over the wired connection only.

Your Mac can stay connected to Wi-Fi for Internet access and other apps. MacDisplay itself, however, remains isolated from that network and communicates only through the cable between your Macs.

The setting is remembered when you quit and reopen MacDisplay, so you don't need to enable it again each time.

A display Mac that macOS remembers

Another improvement is less visible, but makes a real difference in everyday use.

With MacDisplay 3.0, the Mac acting as your second display keeps a consistent identity when it presents itself to macOS. This allows the system to recognize that display again the next time you open MacDisplay.

As a result, macOS can better remember how your displays were arranged and where you left your windows, instead of treating every new session as a completely different monitor.

There's nothing new to configure. Reopening MacDisplay and returning to your usual setup simply feels more consistent.

A completely redesigned in-app guide

With file transfer and keyboard and mouse control joining display extension, the old help window was no longer enough.

The in-app guide has been completely redesigned around MacDisplay's new feature set. Each function now has its own section, and search lets you get directly to the setting or explanation you're looking for.

We've also made device permissions clearer. The first time another Mac wants to send you a file or control your Mac, you decide whether to allow it.

Those permissions are kept in a list and can be reviewed or changed later whenever you want.

• Mac-to-Mac file transferDrag files into the transfer window or the Desktop drop area and send them over Thunderbolt or Ethernet.
• Shared keyboard and mouseThe pointer crosses the edge of your screen and continues on the other Mac. Your keyboard follows.
• Lockdown modeMacDisplay excludes Wi-Fi entirely and communicates over the cable only.
• Consistent display identitymacOS recognizes the Mac used as a display again and remembers your screen arrangement.
• Redesigned in-app guideA section per feature, with search and a clear list of authorized Macs.

What's changing in the free version

MacDisplay still has a free version that does not expire, but version 3.0 changes the way some usage limits are counted.

Display extension and keyboard and mouse control use 10-minute usage blocks. Time is counted while you're using the feature, and disconnecting and reconnecting does not start a fresh block. Once a block begins, it continues until those ten minutes have been used.

After each block, there is a 60-second wait before you can continue.

Free usage is limited to 60 minutes per day in total, shared between display extension and keyboard and mouse control. The daily counter resets at midnight.

File transfer has its own separate allowance: up to 2 GB per day, with a maximum of 2 GB in a single transfer.

Only the Mac initiating the action uses the free allowance. A Mac acting as a display, being controlled, or receiving files does not consume any usage time or file-transfer allowance.

A full MacDisplay license removes these limits from all three functions and covers three Macs.

How to update to MacDisplay 3.0

If you already use MacDisplay, there's nothing else to buy. Version 3.0 is included as an app update and will be offered automatically.

You can also download MacDisplay again from the website. Your existing license will continue to work.

MacDisplay is still, first and foremost, a way to use a Mac as a second monitor. With version 3.0, that second Mac can become a much more complete part of your workspace.

The same connection can extend your desktop, move files between Macs, and let your keyboard and mouse cross naturally from one computer to the other.

Gaetano Andrea Biocca MacDisplay Published on 21 September 2026

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