Looking for ways to salvage an old iMac?

Beatrice Tong

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Mar 10, 2020 · 3 min read

Here is a lazy starter kit for you.

First thing first, take up the courage — clean up storage and upgrade to the latest macOS for your iMac model. Not only does it enhances the layout, but this also boosts the overall speed and usability.

If you’re still not satisfied with the performance because it’s too granny-like (don’t get me wrong, I love my granny), try Target Display Mode! There are simply too many articles out there and I hope these personal tips could help.

What is Target Display Mode (TDM)?

With TDM, you can view the desktop of your Mac on the display of certain iMac models. In other words, you will be connecting iMac as an extended desktop to your MacBook. In this way, your old iMac could perform as if it’s been reborn and potentially raise your productivity!

What would you need?

• MacBook
• iMac — Check iMac model and compatibility here.
• Apple Thunderbolt Cable
• Thunderbolt 3(USB C) to Thunderbolt 2 Adaptor — Depends on your MacBook model

Alternatively, you could purchase a USB C with Mini DisplayPort Cable, which was recommended by an Apple Genius as it performs the same functionality at a cheaper price. Unfortunately, it didn’t work on mine, so be wise and research before purchase.

System software:

High Sierra 10.13.6 or earlier on iMac

(As long as it’s official!)

It is very important NOT to use any patcher, otherwise, TDM might not work. And don’t forget to read Apple’s documentation before any upgrades, I have made a silly mistake hoping to use the sidecar function by upgrading my iMac (mid-2011) with Catalina patcher. However, the hardware simply wasn’t compatible, not to mention it destroyed sleep mode and airdrop too.

If that’s the case, reinstall an officially launched MacOS for your iMac before attempting to use Target Display Mode.

How does TDM work?

1. Connect the Thunderbolt cable to the Thunderbolt ports on each Mac. (Use Thunderbolt adaptor if necessary)
2. Press and hold “command + F2” on the keyboard of external display iMac.

If you experienced a flickering screen 🖥 for a few seconds and nothing actually happened afterwards, do not panic. Here’s what you could do.

1. Check cable condition and connection.
2. Put both Macs at Log Screen and hit “command + F2”, it should eventually work. If not, restart your iMac and try again.
3. Follow the instructions here to reset NVRAM or PRAM, it might do some magic too.

If you have encountered problems with audio output control, check below for troubleshooting.

🔊 Potential Audio Output Issues:

🚨 It only plays on the primary MacBook.

🚨 Secondary iMac speakers won’t play even when it is selected as the output source.

🚨 Audio is alarmingly and uncontrolledly loud on iMac, adjusting audio level shows no effect.

What you could do —

1. Check System Preference > Sound > Switch and test your audio output source.
2. Disconnect TDM, check the audio output of both Macs separately.
3. Reconnect TDM — Try pausing all ongoing audio sources before reconnecting your iMac to MacBook.

If it still doesn’t perform, move on and try again later.

‘Sometimes you need a bit of luck.’

Last but not least, if you’d like to rearrange the position of desktops, adjust audio output and else, simply go to Apple Menu> System Preference > Display > Arrange, you will see all the settings options there. Easy-peasy.

Save the planet, extend the life of digital devices.