Help and support
Check whether your two Macs are compatible, read the answers before you download, and fix the most common problems. Still stuck? A real person replies.
Can I extend the display between my Macs?
The model year is only a rough guide — also make sure that Mac is updated (Apple menu → About This Mac).
The Mac you'll use as the screen
Needs macOS 11 (Big Sur) or later — available on iMacs from 2014 and MacBooks from late 2013.
The main Mac (that extends its screen)
Extending the display requires macOS 12.3 or later. A Mac with an earlier version can receive the display if it runs at least macOS 11.
Macs from 2013-2015 with Thunderbolt 2
For a wired connection, use Ethernet. If a Mac has no Ethernet port, use an adapter compatible with its ports. Extend Display also supports local Wi-Fi. File transfer speed depends on the connection you use.
Before you download
How much does it cost? Is there a subscription?
€29.99 + VAT, paid once, with no subscription and updates included. The license covers up to 3 personal Macs you use to extend the display, control another Mac, or send files. A Mac receiving the display, being controlled, or receiving files is unlimited even for free and does not need a license. Refunds within 30 days.
Can I try it for free?
Yes. The free version never expires and requires no account or credit card. Extend Display and Keyboard/Mouse share 10-minute blocks and a total of 60 minutes per day, with a 60-second wait between blocks. For files: 2 GB per day and at most 2 GB per transfer. Everything resets at midnight. Receiving the display, being controlled, and receiving files are always unlimited.
Where does my data go?
Screen content, files, and control data travel directly between your Macs over the local connection. No cloud, no account, no telemetry. You don't need internet to use it — only to activate a license. With Lockdown, you can block MacDisplay from using Wi-Fi and force a wired connection.
What's the difference from AirPlay or Sidecar?
Sidecar connects an iPad, not a Mac. AirPlay to Mac depends on compatible Mac models, software versions, and receiver settings. MacDisplay supports a true Mac→Mac extension with receiver Macs from macOS 11, including many older iMacs outside Apple's main AirPlay hardware requirements.
Can I watch Netflix or Prime Video on the extended display?
No, and it isn't our choice: macOS blacks out protected video on any shared screen — the same happens with QuickTime screen recording or Zoom screen sharing. But there's a better way: with MacDisplay the second screen is a real Mac, not a passive panel — so open the film on that Mac and drive it with the first Mac's mouse and keyboard. The film plays on one screen, you work on the other, and playback is native, at full quality. Everything else works on the extended display: YouTube, local files, VLC, video calls, video editing.
What do I need to get started?
Open MacDisplay on both Macs. For Extend Display, connect them over Thunderbolt, Ethernet, or local Wi-Fi. File transfer needs a cable: Thunderbolt or Ethernet. For Keyboard/Mouse, the first time you connect, compare the six digits shown on both Macs and allow. When Lockdown is enabled, MacDisplay uses a wired connection only.
How do I use one mouse and keyboard with two Macs?
Open MacDisplay on both Macs and turn on Keyboard/Mouse. The first time you connect, six digits appear on both screens: compare them and allow. Then move the pointer past the edge to control the other Mac, and typing follows the pointer. Press ⌃⌥⌘ to take back control of your own Mac, or ⌃⌥⇧⌘ to take it back and disconnect. Accessibility permission is required on both Macs. The connection is encrypted with AES-256-GCM.
How do I send files to the other Mac?
Connect the Macs over Thunderbolt or Ethernet and turn on File Transfer. Drag files into the “To send” box in the window, or onto the corner panel that stays on your desktop. The first time you connect, the other Mac asks you to allow it. If more than one Mac is on the cable, pick the recipient from the “Send to” menu. The receiving Mac chooses which folder files land in, even the Desktop. You can transfer files while using Keyboard/Mouse; Extend Display must be off.
What is Lockdown for?
Lockdown blocks MacDisplay from using Wi-Fi and forces a Thunderbolt or Ethernet connection. It's mainly for public networks, when you want MacDisplay to communicate over a cable only. It stays on after you quit and reopen the app, and with Lockdown enabled a Wi-Fi connection alone is not enough.
Troubleshooting
Why did Keyboard/Mouse and File Transfer turn off?
When you turn on Extend Display, MacDisplay pauses Keyboard/Mouse and File Transfer: on the same cable, video and files would get in each other's way. As soon as you stop extending, they come back on their own, exactly as you left them. The two of them do work together: you can transfer files while controlling the other Mac.
I can control the other Mac, but the clipboard isn't shared.
Clipboard sharing is optional: check that you turned it on in the Keyboard/Mouse window. Without it, mouse and keyboard still work.
Why can't I send more files in the free version?
Check the sending Mac's allowance: 2 GB per day and at most 2 GB per transfer, reset at midnight. A transfer larger than the credit you have left won't start. The receiving Mac uses nothing. Also check that the Macs are connected over Thunderbolt or Ethernet and that Extend Display is off.
Extend Display: the two Macs can't find each other
If Lockdown is enabled, the two Macs must be connected over Thunderbolt or Ethernet: MacDisplay does not use Wi-Fi. Open MacDisplay on both Macs (one on "Become a monitor", the other on "Extend screen"). From "Continue" on the monitor you have 60 seconds to press "Start connection" on the main Mac. Check System Settings → Network (with a cable: check that Thunderbolt Bridge or Ethernet is recognized; with Wi-Fi: the same network). Antivirus running? Add MacDisplay to the exceptions.
The monitor closes before connecting
It's the 60-second safety: if no main Mac connects within a minute of "Continue", the monitor closes. Reopen it, choose "Become a monitor", "Continue" and start the main Mac within a minute.
Extend Display: black screen or missing permission
The Screen Recording permission is needed only on the main Mac: System Settings → Privacy & Security → Screen Recording → enable MacDisplay, then quit and reopen the app. If that's not enough, remove and re-add MacDisplay in that list and restart the Mac.
Cable connected but not working
Check that the cable is recognized (Network → "Thunderbolt Bridge"/"Ethernet" recognized). It must be a certified Thunderbolt cable or a real Ethernet cable — USB-C "charge only" cables don't work. Unplug, restart both Macs, reconnect.
Slow or stuttering image
On Wi-Fi? Switch to a cable. Wi-Fi only? 5 GHz band and closer to the router. Stuttering even with a cable? Write to support@macdisplay.it with the two Mac models.
Blurry image, or icons too big or too small
Enable HiDPI (Retina) and pick the right preset for the screen; adjust the GUI Density (2.0× is standard).
The monitor Mac goes to sleep by itself
Enable "Keep the Mac awake while receiving" in the monitor window (it's the default).
License problems
Activate the license on the Mac you use to extend the display, control another Mac, or send files: the one receiving doesn't need it. Key not recognized → copy the whole key from the email. 3-Mac limit → MacDisplay menu → License, deactivate one. Email never arrived → check spam or write to us.
Free version limits
Extend Display and Keyboard/Mouse share 10-minute blocks and a single total of 60 minutes per day. Reconnecting or switching between the two does not restart the block: time already used stays used. When a block runs out, you wait 60 seconds before the next one. File Transfer has its own separate allowance: 2 GB per day, with a maximum of 2 GB per transfer. Everything resets at midnight. Only the Mac that extends its display, controls the other Mac, or sends files uses the allowance: a Mac receiving the display, being controlled, or receiving files is always unlimited, even for free.
QuickMonitor: how to use it
Enter "Become a monitor", then the MacDisplay menu at the top → "Export Quick Monitor" → save it to a USB stick. Insert it into the other Mac, double-click, and it's ready. Nothing is installed on that Mac, and nothing is left behind when you unplug the stick.
You'll hear back from a real person — usually within a day.