What to Do With an Old iMac: Repair, Reuse, Sell or Replace

An old iMac is usually worth repairing or upgrading when the job costs far less than a replacement and the machine still has software support left to use. For most Intel iMacs, that support now decides how long they last, not the hardware. In short: an SSD or RAM upgrade still makes sense on most 2012–2019 iMacs you plan to keep, though on a 27-inch 2012–2013 it now costs well over the machine's value; a new screen rarely makes sense on a 2014–2017 5K; and a 2009–2011 model is worth only cheap fixes. Below are the numbers in Australian dollars, a verdict for each model, and what to do if you would rather reuse, sell or recycle it.

How long iMacs last

The hardware in an Intel iMac often keeps running well after Apple stops updating it. Hard drives slow down and fail, and screens, power supplies and fans wear out, but those are all parts that can be replaced. What ends an iMac's lifespan is software. Once its macOS stops getting security updates, and your browser and apps stop supporting it, the machine becomes hard to justify for banking and email, however well it still runs.

Apple has now finished with Intel. Tahoe is the last macOS for Intel Macs, and macOS 27, released on 14 September 2026, runs only on Apple silicon. On the same day Apple patched Tahoe and Sequoia and nothing older. This is where each iMac stands:

• 2009–2017 iMacs on their official macOS (High Sierra to Ventura): outside Apple's regular security updates already.
• 2019 iMacs on Sequoia, and 2012–2017 iMacs patched to Sequoia: Apple has published no end date, but it has recently patched the current macOS and the two before it. On that pattern, our reading is that Sequoia's security updates stop around September 2027.
• 2020 27-inch on Tahoe: on the same pattern, around September 2028. Several outlets have reported Apple promising three years of security updates for Intel Macs, but we have not found that in an Apple document.

A ten-year-old iMac in 2026 is, roughly, a Late 2015 model. On its own it stops at Monterey, which means no current Chrome, no Microsoft 365 updates and no Apple security fixes. With an SSD and a newer macOS through OpenCore Legacy Patcher, it can run Sequoia with security updates until about late 2027. That makes it obsolete for some jobs and still useful for others.

The decision in dollars

Three numbers settle most cases: what the repair costs, what the iMac is worth working, and what replacing it would cost. For the second we use Gumtree asking prices from September 2026. They are asking prices, not sale prices, so treat them as a ceiling. For the third, a new 24-inch M4 iMac is $2,399, a Studio Display is $2,599 if you only need a screen, and refurbished 2019 and 2020 27-inch iMacs in stock at dealers were listed from about $1,600.

Our rule of thumb: if you are keeping the iMac yourself, its resale value matters less than whether the fix carries it to its software cut-off for much less than a new one at $2,399. Spending from $599 on an SSD, or from $848 with newer macOS, on a 2017 5K that can run Sequoia, with security updates, until about late 2027 costs more than the machine would sell for, but a third of a new iMac or less, and you keep the 5K screen. If you like the machine, that trade makes sense. A screen from $1,099 on a Late 2015 5K does not, because working ones are advertised for less than half that. The 2019 no longer adds up: a screen from $1,199 costs half as much again as the machine would fetch, and a working 2020 is advertised privately for about $999. The 2020 is borderline: the same screen costs more than its private value but well under the roughly $1,600 of a refurbished one, and on Apple's pattern Tahoe should outlast Sequoia by about a year, so repair it only if the rest of the machine is sound. If yours will not power on at all, start with our guide to an iMac that will not turn on.

Model-by-model verdicts

2009–2011. These have a separate front glass panel over the LCD, so dust behind the glass and cracked glass are cheap to fix, and the access door takes memory you supply. Anything expensive is hard to justify when a working 27-inch 2011 is advertised for $60 to $150, and Apple's replacement program for the Mid 2011 27-inch graphics card has long expired. On High Sierra, Firefox 115 ESR gets security fixes until March 2027, and no newer macOS is worth installing on stock graphics.

27-inch 2012–2013. An SSD upgrade from $599 makes the biggest difference, and a RAM upgrade through the rear door is from $329 with 16GB fitted. Both cost more than a working one sells for, so do them only if you want this particular iMac; otherwise a used 5K from 2017 or 2019, upgraded, may be better value. Apple's hinge repair program for these models has expired, so a drooping screen now means a hinge repair with us, from $299. The Late 2012 blade slot takes only SATA blade SSDs, one of several details we check before quoting.

21.5-inch 2012–2019. Every job inside means cutting the glued display free and fitting new adhesive. RAM is soldered on the Mid 2014 and all Late 2015 models, so on those an SSD is the only speed upgrade. On the 2012–2013, 2017 and 2019, adding 16GB with the SSD costs from $249 extra because the display is already off.

27-inch 5K. These are the most rewarding to upgrade, with rear-door RAM and room for an SSD. A 5K panel alone costs about $745 retail, though, which is why screen replacement rarely adds up on a 2014–2017. The 2020's SSD is soldered to the logic board, so extra storage has to be an external Thunderbolt drive.

Using an old iMac as a monitor

Some iMacs can act as a display for another Mac using Target Display Mode. Apple limits it to these iMacs, in its own words:

• "Any iMac introduced in 2011, 2012, 2013 or mid 2014 using macOS High Sierra 10.13.6 or earlier", connected with a Thunderbolt or Thunderbolt 2 cable.
• "Any 24-inch or 27-inch iMac model introduced in 2009 or 2010 using macOS High Sierra 10.13.6 or earlier", connected with a Mini DisplayPort cable.

In practice that covers the 27-inch Late 2009 and Mid 2010, the 21.5- and 27-inch 2011 models, the Late 2012, Early 2013 and Late 2013 models, and the 21.5-inch Mid 2014. The 21.5-inch Late 2009 and Mid 2010 cannot do it, and neither can any iMac from Late 2014 onwards, which includes every Retina 4K and 5K model. The High Sierra condition matters too: a 2012–2014 iMac that has been updated to Catalina or Big Sur no longer meets Apple's stated requirement.

The computer you connect has to qualify as well. Apple lists "Any Mac introduced in 2019 or earlier using macOS Catalina 10.15.8 or earlier", and Target Display Mode does not support Boot Camp or Windows. A current Apple silicon Mac or a Windows PC is not on that list. If both machines qualify, press Command-F2 on the iMac's keyboard to switch.

Selling it, and wiping it properly first

If you sell or trade in an iMac, compare any offer against private asking prices. On Gumtree in September 2026, working Intel iMacs were advertised for $60 to $150 (27-inch 2011), about $220 (27-inch 2012–2013), about $400 (27-inch 5K Late 2015), about $475 (27-inch 5K 2017), about $500 (21.5-inch 4K 2017), about $799 (27-inch 5K 2019) and about $999 (27-inch 5K 2020).

Before it goes, back up, then sign out of your Apple Account in the iMac's settings, which also turns off Find My. How you factory reset it depends on the model:

• 27-inch 2020: the only Intel iMac with Apple's T2 chip, so it can use Erase All Content and Settings, which needs either Apple silicon or a T2.
• Every other Intel iMac, 2009 to 2019: start up in macOS Recovery (hold Command-R as it starts), use Disk Utility to erase the internal drive, then choose Reinstall macOS so the buyer gets a working machine.

If the iMac runs a patched macOS, tell the buyer, because they will need to update it by hand. If it will not start at all, your files may still be on the drive, and our data recovery service (from $249 while the drive is readable) can get them off before it goes.

Recycling it

If it is not worth repairing or selling, keep it out of the household bin and take it to an e-waste drop-off, such as a council collection point or an e-waste recycler, after erasing it or removing the drive. Faulty iMacs still have some value as parts: non-working 27-inch 2011 units are advertised for about $55 to $65, and faulty 27-inch 5K 2017 models for $200 to $249, so a "for parts" listing is worth trying first.

When we would tell you to replace it

• A 2009–2011 iMac with a fault that costs more to fix than the machine would sell for.
• A 2015 or 2017 5K whose screen has failed, because a working one is advertised for less than the new panel costs.
• Usually, a 2019 5K with a failed screen, since a working 2020 is advertised for less than the repair, which is from $1,199.
• Any iMac that must run a supported macOS beyond late 2027 for work, other than a 2020 on Tahoe.
• Anyone who wants Apple Intelligence, which none of these machines can run.

In most other cases, repairing or upgrading wins, and the full iMac price list shows what each job costs. We are near Castle Hill, iMacs are drop-off only, and we are open Monday to Saturday, 8am to 6pm. The phone quote is free. The iMac repair and upgrades hub has everything else we do.

Call 0400 454 859

Questions

Can I use my old iMac as a monitor for a new MacBook?

Not with Apple's Target Display Mode. Apple's list of connecting computers stops at Macs introduced in 2019 or earlier running Catalina or earlier, and the mode does not support Windows. The iMac itself must also be an eligible 2009 to 2014 model running High Sierra 10.13.6 or earlier. For a 5K iMac, a third-party driver-board conversion is the only route, and we do not fit those.

How much is my old iMac worth in Australia?

Going by Gumtree asking prices in September 2026, a working 27-inch 5K 2020 is advertised for about $700 to $1,750, a 2019 for about $400 to $999, a 2017 for $400 to $599, a Late 2015 for $350 to $650 and a 27-inch 2012 or 2013 for $100 to $350. These are asking prices, not sale prices, so you may need to accept less.

Is it worth putting an SSD in a 2012 iMac?

Only if you want to keep that particular machine. From $599 with a 500GB SSD, data transfer and macOS setup, it removes the hard drive bottleneck and is the foundation for running Sequoia through OpenCore Legacy Patcher. Working 27-inch 2012 and 2013 iMacs are advertised for about $220, so the upgrade costs well over the machine's value and will not come back when you sell. If you are not attached to it, a used 27-inch 5K from 2017 or 2019 with an SSD can be better value.

Do I need to reinstall macOS after erasing an iMac?

Yes, if you want the buyer to receive a working computer. Erasing the internal drive in Disk Utility removes macOS along with your data, so the iMac will not start normally until macOS is reinstalled from the same Recovery screen, which needs an internet connection. The 2020 27-inch is the exception, because Erase All Content and Settings leaves macOS installed and ready for the next owner.

Can I still use a 2011 iMac for internet banking?

For now, but the window is closing. Banks ask you to keep your browser up to date, and on High Sierra, the last macOS for a 2011 iMac, the only one of Chrome, Safari and Firefox still receiving security fixes is Firefox 115 ESR, which gets them until March 2027. Apple no longer patches High Sierra itself. After March 2027, we would not use it for banking.

Is it worth buying a used Intel iMac in 2026?

Only at the right price, and with the software cut-off in mind. The 27-inch 2020 runs Tahoe, which on Apple's usual pattern should receive security updates until about late 2028. Every other Intel iMac tops out at Sequoia, officially or through the patcher, with updates to about late 2027 on our reading. Check the drive type, and on a 2020, buy the storage you need, because it cannot be upgraded internally.

What should I do with an iMac that will not turn on?

Find out why before you decide. It could be the power supply, which we replace from $399 on a 21.5-inch and from $479 on a 27-inch, or a fault on the logic board. Our $150 bench diagnostic tells you which, and it is waived if you proceed. If the repair is not worth it, the drive may still hold your files, and data recovery starts from $249 while the drive is readable.