Selling a Mac without properly wiping it is not just a privacy risk to you — it can leave the buyer with a machine still tied to your Apple ID, unable to activate it at all. Apple's Activation Lock will refuse to let a new owner set up a Mac that's still associated with your account, and that's the most common reason a "clean" second-hand Mac gets returned. This checklist covers the steps in the order that avoids both problems: your data gone, and the machine genuinely ready for someone else.

Back up first, properly

Before you touch any settings, make a backup you'd actually trust to restore from. Time Machine to an external drive is the simplest option; if you use it, let a full backup finish and verify it by browsing a few folders in Time Machine's interface before continuing. If you're moving to a new Mac, Migration Assistant can pull directly from this backup later, so there's no rush to reconstruct anything manually.

Don't skip this because you "already have everything in iCloud." iCloud Photos, Desktop and Documents sync, and Messages in iCloud are convenient, but they are not a substitute for a real backup you control — you're about to remove the Mac from your Apple ID, and unlinking can behave unpredictably if the backup is still mid-sync.

Sign out of iCloud

Go to System Settings → [your name] and choose Sign Out. macOS will ask whether to keep a copy of iCloud data (Photos, Contacts, Calendars, and so on) on this Mac before you erase it — since you're erasing it, this choice barely matters, but choosing to keep a local copy briefly gives you one more chance to check nothing important is iCloud-only and unsynced.

This step also removes the Mac from Find My, which matters because a Mac still enrolled in Find My when erased can trigger Activation Lock on the next setup, even after a full erase.

Sign out of Messages, and deauthorize iTunes/Music content

Messages in iCloud syncs across your devices, but the Messages app itself keeps a local login. Open Messages → Settings → iMessage and sign out, otherwise the buyer could theoretically see message previews arrive briefly before their own setup completes.

If you have DRM-protected purchases from the iTunes Store era, open Music → Account → Authorizations → Deauthorize This Computer. Apple limits the number of authorized machines per account, and forgetting this step quietly uses up one of your slots on a Mac you no longer own.

Sign out of any other accounts with local state

Work through anything that keeps credentials or synced data on the machine: Chrome or Firefox profiles, Slack, any VPN client, password managers with a local vault, and cloud storage clients like Dropbox or Google Drive (unlink the account, don't just quit the app). None of these are cleared by Apple ID sign-out or even by Erase All Content and Settings if you've forgotten to remove browser-saved passwords from a profile you're exporting elsewhere first.

Remove old iOS backups you don't need anymore

If you've ever backed up an iPhone or iPad to this Mac via Finder, those backups live in ~/Library/Application Support/MobileSync/Backup/ and can be 5–15GB each. They serve no purpose to the buyer and there's no reason to carry them into your restored backup either — delete them from Finder's own backup management (Finder → [device] → Manage Backups) before you back up the Mac, not after.

Erase All Content and Settings

On Apple Silicon Macs running a recent macOS, System Settings → General → Transfer or Reset → Erase All Content and Settings is the correct tool. It's built for exactly this handover: it removes your Apple ID, wipes user data, and returns the Mac to a state indistinguishable from new, without requiring you to reinstall macOS from a recovery image.

Run it only after confirming:

  • Your backup is complete and verified
  • You've signed out of iCloud, Find My, Messages, and iTunes authorization
  • Any FileVault recovery key you might need is saved somewhere other than this Mac

The process reboots into Setup Assistant when done — that's the buyer's starting point, not yours.

What Erase All Content and Settings does not clean up for you

The eraser handles the OS volume thoroughly, but it's worth knowing what it doesn't touch: anything on an external drive left connected during the process, and any encrypted backup password you've stored only in this Mac's keychain (you'll need it later, so retrieve it before wiping, not after). It also doesn't verify that you actually removed the device from Find My beforehand — if you skip that step, the eraser will still run, but the buyer may hit Activation Lock regardless.

Do a final sanity check before handover

Boot into Setup Assistant once (without configuring anything) to confirm it reaches the "Hello" welcome screen rather than an Activation Lock prompt asking for your Apple ID and password. That's the definitive sign the Mac is genuinely ready for a new owner. If it does ask for your credentials, sign in, remove the device from Find My properly, and erase again.

What to have ready for the buyer

A second-hand Mac is more attractive, and easier to answer questions about later, if you hand over a short written summary alongside it: the macOS version it shipped with, any known hardware quirks, and confirmation that Activation Lock has been cleared. If the Mac came with its original box or documentation, include it — Apple support sometimes asks for proof of original ownership during a warranty or AppleCare transfer, and a serial number match to the original packaging speeds that up considerably.

If you're trading in through Apple or a reseller rather than selling directly, most of them run their own verification that the device isn't still tied to an account, which is a useful independent check that your erase actually completed properly. A private sale doesn't have that safety net, which is exactly why the sanity-check step above matters more in that case.

If FileVault is enabled

Most Macs sold in the last several years have FileVault disk encryption on by default. Erase All Content and Settings works cleanly with FileVault enabled — you don't need to disable encryption first — but it's worth confirming you have the recovery key saved somewhere other than the Mac itself (in your Apple ID account recovery keys, or written down) before you start, in case the erase process is interrupted and you need to unlock the drive to try again.

Where VolumeLens comes in, before you erase

If you want a last look at what's actually on the disk before wiping it — confirming there's nothing personal left in an old Downloads folder, an overlooked project, or a forgotten Documents subfolder — a storage map is a faster way to check than browsing Finder folder by folder. VolumeLens scans locally, shows every folder by size, and never uploads anything, so a last check before you sell doesn't create a new privacy question of its own.