dual screen

ajejap wrote:

I have a new iMac on MAC OS Monterey and want to dual screen too an old Mac running High Sierra. I have purchased a thunderbolt cable from the apple store. after discussing with the team what I want to do. Ive followed the instructions using Command F2 but nothing happens. Ive watched so many tube vids I can't see what is wrong- any ideas?

While the old iMac (depending on the model) may support Target Display Mode.

The new iMac's built after 2019 do not support using an old supported iMac as a display.

please carefully read > Use your iMac as a display with target display mode - Apple Support

I've been to the Apple store twice and clearly explained what I had and what I wanted and they said it could be done. I will go back tomorrow and return the thunderbolt cable they sold me.

A Thunderbolt 3 to Thunderbolt 3 cable could be handy down the road, but I would defiantly return a Thunderbolt 3 to Thunderbolt 2 adapter.

Can you use a standard (non Mac) monitor?

Yes you bet, in fact most any modern external display can be connected to the new iMac.

see > Connect an external display to your iMac - Apple Support

Target display mode is a feature that was available only with certain older iMac models.

Only the following older iMac models can be used as an external display when plugged into another older Mac model:

• iMac models introduced in 2011, 2012, 2013, and mid 2014 using Thunderbolt or Thunderbolt 2 cable.
• 24-inch and 27-inch iMac models introduced in 2009 and 2010 using Mini DisplayPort cable.
• The intended target iMac must be running macOS 10.13 High Sierra or earlier; it does not work with macOS 10.14 Mojave or later, or with Boot Camp and Windows.
• Retina display iMacs won’t work as target displays.
• In all cases the source Mac that you're connecting FROM must have been introduced in 2019 or earlier and have macOS 10.15 Catalina or earlier installed.

Target Display Mode has been abandoned by Apple. Macs newer than the 2019 don't support it in any fashion. Apple Silicon Macs don't support it.

Do yourself a favor and buy a second monitor.

You’re welcome.

Yes, you can use most any monitor on the market with your Mac. HDMI connections are very commonly used with the Mac.

You haven’t told us which Mac model and year that you have, so we can’t be any more specific about the connection method that’s best for your situation.

I will go back tomorrow and return the thunderbolt cable they sold me.

Print out the article that den.thed links and take it with you. We are seeing too many reports of Apple employees believing the post-processed horse feed about Target Display Mode on the internet instead of reading their company's official support document.