Is it possible to use iMac Catalina with Mac Mini 4?

Your tag line says that you have a 21.5" iMac.

In 2010, the 21.5" models did not feature Target Display Mode. Only the 27" models did. In addition, Apple later added restrictions on the video source that mean that a M4 Mac mini or M4 Pro Mac mini is too new to use ANY iMac as a Target Display – even an iMac that supports the Target Display Mode feature.

See the bad news here: Use your iMac as a display with target display mode - Apple Support

Although that 21.5" iMac display has decent quality, it's still just a 1920x1080 pixel display. Today you can get

• Cheap 24" 1920x1080 pixel monitors with terrible color accuracy for $80 USD or so.
• 24" 1920x1080 pixel monitors with IPS panels and near-100% coverage of sRGB for $150 USD or so.
• 27" 3840x2160 pixel monitors with IPS panels and near-100% coverage of sRGB for as little as $300-$350 USD.

A 27" 3840x2160 pixel display has 2.25x as many pixels as a 27" 2560x1440 one, in the same physical area, and so a 27" 3840x2160 pixel display running in Retina "looks like 2560x1440" mode will look better in some ways than an actual 27" 2560x1440 pixel monitor.

Niel wrote:

>In 2010, the 21.5" models did not feature Target Display Mode.

>2010 iMacs do not have Thunderbolt.

Since that iMac is running Catalina, it's not a 2010 model.

(257090)

Good catch. I must have read the title "connecting iMac 201 t0 Mac Mini 4" (where the OP typed a '0' after 't', instead of an 'o') the wrong way.

If the OP has a 21.5" Late 2012, Early 2013, Late 2013, or Mid 2014 iMac, it would have a Thunderbolt port, and would support Target Display Mode using Thunderbolt input – when running High Sierra or earlier.

That still wouldn't help the OP, because the M4 and M4 Pro Mac minis are too new to use any iMac as a Target Display.

harrykim wrote:

Late 2012 model

APPLE Store helpers sail this, with the Thunderbolt 2-3 adapter , plus another link, would be ok for new Mac Minji.

That adapter, plus a Thunderbolt 1/2 cable, would let you make a Thunderbolt data connection. A Thunderbolt 1/2 cable is like a Mini DisplayPort to Mini DisplayPort cable (same connectors), except higher grade – built to be able to reliably carry a Thunderbolt data signal.

With that, you might be able to

• Put the old iMac into Target Disk Mode, where it acted like a directly-attached external disk for the new Mac.
• Set up Thunderbolt Bridge Mode (IP-over-Thunderbolt) on both Macs and use the Thunderbolt connection in much the same way as a direct Ethernet-to-Ethernet network connection (that didn't go through a router).

Even if you made a Thunderbolt connection and downgraded the old iMac to High Sierra, a new Mac mini wouldn't support using the old iMac as a Target Display. The M4 and M4 Pro Mac minis

• Were released after 2019
• Can only run versions of macOS later than Catalina

and Apple's Support article says that the video source must be a Mac released in 2019 or earlier, which is running Catalina or earlier.

There aren't any solutions which don't require a standalone monitor for the Mac mini. If you have one, set up Virtual Network Computing.

(257089)

If you're trying to use it as a display directly, no.

If you're trying to use it as a display through Virtual Network Computing or any other type of data link, no additional cable or adapter is required.

(257091)

harrykim wrote:

What additional links do I need (I have a Thunderbolt 2 to 3 adapter)?

2010 iMacs do not have Thunderbolt. If you run a "Thunderbolt" connection from a modern Mac to a 21.5" 2010 iMac's Mini DisplayPort output port with the help of a $50 Apple TB 3-to-2 adapter and a $30+ TB 1/2 cable, the BEST you can hope for is that nothing will happen. You'll be sending a type of signal (Thunderbolt) into that old iMac that it was never designed to accept.

You won't even get a working data connection – let alone a working display one.

If by any chance you are talking about a USB-C to Mini DisplayPort adapter (same physical connectors, different signal type), that won't work either, as 21.5" 2010 iMacs never had the ability to accept external video signals.

>In 2010, the 21.5" models did not feature Target Display Mode.

>2010 iMacs do not have Thunderbolt.

Since that iMac is running Catalina, it's not a 2010 model.

(257090)