How to prepare an iMac for sale and wipe it

An iMac rarely leads the life a laptop does. It sits in one corner of a kitchen or spare room for years, collecting everyone’s photos, three generations of printer drivers and whatever the kids logged into. Preparing one for sale is less a quick tidy than untangling the household filing cabinet. Take the three ordered steps below — back up, sign out, erase — then twenty minutes on the physical side.

More than you want to take on? Say so when you sell your iMac — we wipe at intake. The one part we genuinely need from you is the sign-out.

1. Back up, and check what is actually on there

Everything after this point is irreversible. Plug in an external drive, open System Settings → General → Time Machine, add the disk and let a full backup finish. On a desktop in service since the Fusion Drive era, expect a long evening. Then go looking for what people miss on a family machine:

• Other user accounts. Check System Settings → Users & Groups. A second or third account often holds a partner’s documents or a child’s coursework, and backing up your own does not surface them.
• Photos libraries that never reached iCloud. Open Photos, see which library it is using, and confirm whether iCloud Photos was ever switched on.
• Local-only folders and mail. Downloads, Movies, a secondary account’s Desktop and POP email all go with the erase.
• Licence keys for anything bought outside the App Store.

Moving to a newer Mac? Back up first, then pull it across with Migration Assistant — the backup does double duty.

2. Turn off Find My and sign out of your Apple Account

This step decides whether your iMac is worth selling at all. Find My applies Activation Lock, tying the machine to your Apple Account at firmware level. A locked iMac cannot be set up by anyone else and drops to roughly parts value — on an all-in-one, a fraction of the whole. No buyer, ourselves included, can clear it for you.

Open System Settings, select your name at the top, scroll to the bottom of that panel and choose Sign Out. You will need your Apple Account password. macOS offers to keep contacts and calendars locally; it makes no difference, as the erase removes them anyway.

If the iMac has already left, sign in at iCloud.com, open Find My and Remove from account.

3. Clear the smaller sign-outs and unpair the peripherals

• Messages → Settings → iMessage → Sign Out, so nothing routes to a Mac in someone else’s house.
• Music → Account → Authorisations → Deauthorise This Computer. Apple caps how many machines hold an authorisation, so take the slot back.
• Bluetooth peripherals. Particular to a desktop. Keeping the Magic Keyboard, Mouse or Trackpad for another machine? Unpair them in System Settings → Bluetooth. If they go with the sale, leave them paired and hand them over together.

4. Erase: which route your iMac takes

Two procedures, and the dividing line is the security chip rather than the year.

Erase All Content and Settings covers the 24-inch M-series iMacs, the final-generation 27-inch Retina 5K and the iMac Pro — the last two carry Apple’s T2 chip, which is what makes the tool available. Go to System Settings → General → Transfer or Reset → Erase All Content and Settings, enter your password, sign out when prompted and confirm. The Mac destroys the encryption key, removes your accounts, releases Activation Lock and restarts to the setup screen with macOS still in place. Whole job, one pass, macOS Monterey or later.

Recovery and Disk Utility covers the older Intel bodies: the earlier 27-inch 5K bodies, the 21.5-inch 4K and non-Retina models, and anything on an older macOS. Restart holding Command + R until the Apple logo appears. A desktop-specific snag — a Bluetooth Magic Keyboard sometimes reconnects too late for that combination to register, so if the first attempt boots normally, borrow a wired USB keyboard. In Recovery, open Disk Utility, select the internal drive and erase it as APFS, or Mac OS Extended (Journaled) on much older machines. Quit Disk Utility and choose Reinstall macOS. On a Fusion Drive, erase the combined volume rather than the SSD and hard disk separately; if the pairing has already split, leave it and tell us — that is a known fault, not a doorstep repair.

5. Do you need to reinstall macOS?

Not always. Erase All Content and Settings leaves a working system behind, so the machine boots to the Hello screen and you are finished. After a Recovery erase the drive is empty, and an iMac that powers on to a flashing question mark looks broken even when it is sound — so reinstall there.

Rather not sit through an hour of progress bars? Sign out, tell us it is erased but not reinstalled, and we put a clean macOS on it at intake, as we do with every machine.

Cleaning an all-in-one without ruining the panel

The screen is the most valuable component and the one most readily damaged by good intentions. Apple’s displays carry an anti-reflective coating, and household glass cleaner, ammonia, kitchen spray and alcohol wipes all strip it, leaving a cloudy, patchy finish that is permanent.

• Screen: power down and use a dry microfibre cloth, dampened with plain water only if something needs shifting. Never spray at the panel; liquid runs behind the bezel.
• Chin and back: the aluminium takes a slightly damp cloth. Fingerprints around the badge and bottom edge show up in photos.
• Stand and foot: wipe the base and check the hinge holds position. A stand that sags is worth mentioning in your quote.
• Vents: dust gathers in the slot along the back edge. A soft brush, or compressed air from a distance, is plenty.

Go no further. The 27-inch display is held on with adhesive and the 24-inch is bonded glass; opening either takes cutting tools and fresh adhesive.

Gather everything that goes with it

• The stand, or the VESA mount plate if the machine was wall-mounted — a VESA body without its plate is awkward, so dig it out
• Magic Keyboard and Magic Mouse or Trackpad, plus the Lightning or USB-C cable each charges with
• The power lead — some 24-inch configurations use a magnetic connector and an Ethernet brick, which no plain lead replaces
• Any adapters from the box, and the box itself if it is in the loft

List the lot in your quote. Missing pieces do not stop us buying, though a complete machine is worth more; the what’s my iMac worth guide covers the specification side.

What not to do

• Do not attempt a screen repair. A cracked all-in-one panel is close to uneconomic to fix, and a half-finished attempt with the adhesive cut turns a repairable machine into parts. Photograph the damage instead.
• Do not pull the RAM from a 27-inch. The hatch tempts people into keeping their upgrade. It costs more on the offer than the sticks are worth to you, and empty slots read as stripped.
• Do not scrub the panel, and skip the polish, glass cleaner and disinfectant wipes.
• Do not open the case. Nothing inside needs your attention before it sells.

Handing it over

You will notice there is no packing step here. Deliberate — bonded glass cracks in transit even in a good box, so we collect from your door rather than send you to a courier counter with a 27-inch screen under one arm. Leave it on the desk, keyboard and mouse alongside. Payment happens there, once we have confirmed it matches your description and is signed out.

Ready? Sell your iMac and tell us the model, the chip, the storage and how far down this list you got. Free UK collection, paid on exchange.