Questions
Frequently asked.
Including the ones where the answer is no. If yours is not here, write to [email protected].
The basics
Can I use my iMac as a monitor for my MacBook?
Yes, that is exactly what DisplayBridge does. You install the app on both Macs, connect them with a Thunderbolt cable and click Connect. The iMac then shows a second desktop belonging to the MacBook, and macOS treats it like any monitor you would plug in.
Which Macs can act as the display?
Any Mac running macOS 13 Ventura or later, Intel or Apple silicon, with a Thunderbolt 3 or later port. The Mac showing the screen never needs a license, so there is no cost to trying it on an old machine.
Which iMac do I need for 5K at 60 Hz?
A Retina 5K iMac from 2017 or later: the iMac (2017), iMac Pro, iMac (2019) or iMac (2020). Those are also the oldest 5K iMacs with Thunderbolt 3 ports. Support for the 2015 model as a receiver is planned.
Which Mac gets 120 Hz?
A ProMotion MacBook Pro used as the display: the 14-inch and 16-inch models from 2021 onward. Those are the Mac panels that can actually show 120 frames per second.
What cable do I need?
A Thunderbolt 3 or Thunderbolt 4 cable, or a USB-C cable rated for USB4 at 40 Gb/s. A charge-only USB-C cable looks identical and will not work — if the two Macs never find each other, suspect the cable.
Will it work over Wi-Fi or Ethernet?
No, and it never will. A full 5K picture at 60 Hz is about 10.6 Gbit/s. Wi-Fi and Gigabit Ethernet are one to two orders of magnitude short of that, so anything wireless has to throw most of the picture away. We would rather ship one path that always works than four that sometimes do.
What it is, and what it is not
Is this Target Display Mode?
No. Target Display Mode was an Apple feature of iMacs from 2009 to 2014 and was removed with macOS Catalina in 2019. The Retina 5K iMacs never had it. DisplayBridge is software and works on Macs that never supported Target Display Mode.
Is this Sidecar?
No. Sidecar turns an iPad into a second screen for a Mac and is built into macOS. DisplayBridge turns a Mac into a second screen for another Mac, which Sidecar cannot do.
Can I control the sending Mac from the other one's keyboard and mouse?
No. There is no input relay. The receiving Mac is a display, not a remote-control session. We would rather say that plainly than imply otherwise.
Can I keep using the receiving Mac at the same time?
Not while it is showing the other Mac's screen — the picture fills its display. Its own desktop is still running underneath; press Esc on that Mac, or stop the session from the sending one, and you are back on it immediately.
Does sound come across too?
Yes. Audio travels down the same cable, and you can choose whether it plays on the receiving Mac, on your own speakers, or both. The brightness and volume of the receiving Mac can be driven from the session card as well, so it behaves like a monitor there too.
Can I use two Macs as displays at once?
Yes. Two 5K displays at 60 Hz from one Mac is supported.
Privacy, permissions and safety
What permissions does it need?
Two. Screen Recording on the sending Mac only, because macOS classes reading the pixels of a desktop as privileged. Local Network on both Macs, so they can find each other over the cable. No admin password, no kernel extension, no login item.
Does anything leave my Mac?
Your screen never does. The picture travels down the cable between the two Macs and stops there — no server, no router, no internet. The app does send an anonymous signal that it launched and that a session started, plus the app and macOS version, and nothing about your screen or your files.
Does it need an internet connection?
Only once, to activate your license. After that it streams entirely offline. The app re-checks the license occasionally and is deliberately generous about not being able to, so an outage never interrupts a running session.
Buying it
Do I need to buy it twice, once for each Mac?
No. Only the Mac sending its screen is licensed. The Mac showing the picture is free, forever, on as many machines as you like. That is why there is one app instead of two.
How many Macs does one license cover?
Three sending Macs at a time, for one person, for a one-time $29. Receiving Macs are unlimited and never counted.
What happens if a Mac is lost, wiped or sold?
Nothing you have to deal with. If you hit the three-Mac limit, activating a new one automatically retires the oldest inactive activation. The key from your purchase email always works.
Is there a trial?
Seven days, everything unlocked, no credit card and no account sign-up. Afterwards the app keeps working as a display indefinitely; starting a session from that Mac is what needs a key.
Can I get a refund?
Within 14 days of purchase, through Lemon Squeezy, who handle the sale. The seven-day trial exists so you can check it on the exact Macs and cable you intend to use before paying anything.
Practical
Does it work on Intel Macs?
Yes. It is a universal app and runs natively on both Intel and Apple silicon, on either end of the cable.
How big is the app?
About 6 MB, everything included. No installer, no runtime to download, no Electron.