Use a 2009 iMac
as a second screen.
Yes. A Late 2009 iMac can be a second screen for any Mac on macOS 14 or later, over Wi‑Fi or a cable. An Early 2009 iMac works too, with Encore Receiver Legacy. Apple's Target Display Mode can't do this with a Mac from 2020 or later.
The 2009 iMac at a glance.
- Models
- iMac (21.5-inch, Late 2009), iMac (27-inch, Late 2009)
- Newest macOS
- macOS 10.13 High Sierra
- Cable
- Gigabit Ethernet, or Wi‑Fi
- Expected picture
- Up to the panel's size, 30 to 60 fps
- Target Display Mode
- 27-inch only, over Mini DisplayPort, with a Mac from 2019 or earlier
- AirPlay to Mac
- No
- Your Mac
- macOS 14 Sonoma or later, Apple silicon or Intel
What works.
Everything Encore does, on the 2009 iMac.
An extra desktop
Drag windows onto the iMac as onto any monitor.
Its keyboard and mouse
The iMac's own keyboard and mouse can control your Mac. Press Control-Option-Command-Esc on the iMac to switch back.
Its speakers
Your Mac's sound can play on the iMac's speakers, on one or several iMacs at the same moment.
Several iMacs
More than one iMac at once, each with its own Connect button.
StandBy
When it isn't a screen, the iMac shows a clock, the weather and your calendar.
The picture
Up to the panel's size, 30 to 60 fps. Expected, not yet measured on every model.
The right download.
One app for your Mac, one for the iMac. Free during the public beta.
Encore Receiver, on the iMac
The Late 2009 iMac runs up to macOS 10.13 High Sierra, so it uses Encore Receiver. The Early 2009 models stop at OS X 10.11 El Capitan and use Encore Receiver Legacy, which decodes in software and sends a smaller picture (about 1440 × 900).
Download Encore Receiver
Encore, on your Mac
It finds the iMac, sends the picture and holds every switch. Both apps update themselves.
Download EncoreAn Early 2009 iMac on OS X 10.10 or 10.11? Download Encore Receiver Legacy. It decodes in software, so the picture is sent smaller (about 1440 × 900) and scaled up.
Which cable.
Your iMac has a Gigabit Ethernet port and no Thunderbolt, so Ethernet is the way. Wi‑Fi needs nothing. For the sharp, lossless picture, everything in between must carry at least 400 Mbit/s: never a 10/100 adapter.
Gigabit Ethernet
- A USB-C to Gigabit Ethernet adapter for your Mac. It must say Gigabit or 10/100/1000. Skip it if your Mac has an Ethernet port.
- A Cat6 Ethernet cable (Cat5e also works), long enough to reach the iMac.
- Plug the cable into the Ethernet port on the back of the iMac.
Up to 1000 Mbit/s: the sharp, lossless picture, and Ultra on a 1080p screen.
Wi‑Fi
- Nothing to buy. Both Macs on the same network, on 5 GHz.
- The picture is compressed while things move and exact again once the screen is still.
Typically 50 to 400 Mbit/s on 5 GHz, depending on the iMac's radio.
Apple's own options.
Target Display Mode
Only the 27-inch Late 2009 iMac, over a Mini DisplayPort cable. The 21.5-inch Late 2009 is not on Apple's list. (Apple's list also names the 24-inch iMac from early 2009.)
Whatever the iMac, Apple requires the Mac that connects to be from 2019 or earlier, on macOS Catalina 10.15.8 or earlier. So no Mac with Apple silicon. Source: Apple's support page.
AirPlay to Mac
No. Receiving AirPlay on a Mac needs an iMac from 2019 or later on macOS 12 Monterey or later.
Paid apps, a capture card or a display driver board are other routes. We compared them all, with sources, in every way to use an old iMac as a monitor. Why Apple's option ended: Target Display Mode explained.
Questions about the 2009 iMac
Can a 2009 iMac be a monitor for an M1, M2, M3 or M4 Mac?
Yes, with Encore, over Wi‑Fi or a cable. Target Display Mode can't, because Apple requires the connecting Mac to be from 2019 or earlier on macOS Catalina or older.
Does the 2009 iMac support Target Display Mode?
Only the 27-inch Late 2009 iMac, over a Mini DisplayPort cable. The 21.5-inch Late 2009 is not on Apple's list. (Apple's list also names the 24-inch iMac from early 2009.)
Which cable connects a Mac to a 2009 iMac?
Your iMac has a Gigabit Ethernet port and no Thunderbolt, so Ethernet is the way. The connection must carry at least 400 Mbit/s, so Gigabit Ethernet. Wi‑Fi works without any cable.
Will the 2009 iMac's keyboard, mouse and speakers work with my Mac?
Yes. The iMac's keyboard and mouse can control your Mac, and your Mac's sound can play on the iMac's speakers.
Can the 2009 iMac be a clock or smart display?
Yes. When it isn't your second screen, the iMac shows StandBy: a clock, the weather and your calendar. It can also play AirPlay music, with the album on a turning record.
What does Encore cost?
Free during the public beta, if you report what goes wrong. No subscription, no account.
