Recently, someone on Hackathon Hackers asked for advice on buying a 2013 MacBook Air. I reassured them that it would be more than powerful enough for software development work. However, their post also reminded me of the paranoia associated with buying used things.

There’s already great advice for buying used computers in general, so the following is my advice for Macs specifically:

  • See if a refurbished Mac would be a better deal instead. These are carefully inspected and repaired by Apple technicians and are accompanied by a 1-year warranty. They’re also a great way to acquire the latest Mac at a lesser cost.

  • If an official refurbished Mac would cost too much, try to find a seller on a computer hardware-dedicated forum, like Overclock.net. Be sure to check their reputation on the forum. Have all of their previous deals completed without complaint? How many items have they bought/sold before? How long have they been on the site? Do their non-marketplace posts seem credible or is this a scammer setting up a smokescreen identity?

  • Once a seemingly-good seller is found, arrange to meet with the seller in a public place like Starbucks, with lots of foot traffic, free WiFi, and sitting in good view of surveillance cameras. Bring a friend if possible and let others know where you’ll be (and when). Be prepared to walk away from the deal and take transportation to somewhere safe. As always, it’s best to conduct such transactions in broad daylight.

  • Remind them that you’ll be fully wiping this Mac before configuring it for yourself. Thus, now is the time for them to remove any data of theirs that they do not want to lose. However, ask them to hold off on wiping the Mac themselves, as you want to verify that it’s not stolen. Ask them to bring any original receipts, records of repairs, and any warranty documentation.

  • Once there, greet them cordially and chat them up and check their supposed background and identity. Trust your instincts and carefully consider any red flags that appear. For example, absolutely refuse any offer to buy a MacBook in a shrink-wrapped box without being able to inspect it. Scammers often replace their contents and then re-wrap them.

  • Now we have to check the Mac itself. Begin by asking the seller to reveal any flaws that they do know of, letting them know that is to their negotiating advantage to disclose them now, openly and honestly.

  • Check that the laptop matches your expected configuration. For example, a 2013 MBA has two USB ports, two Thunderbolt ports, an SD card slot, and tapers from thick at the screen to thin at the trackpad. In the menubar, we can get details via the Apple icon -> “About This Mac” and also “System Report”.

  • Then, run through this checklist:
    • Ask them to carefully remove any case so that you can check for scratches, dings, dents, and so on.
    • Point out any flaws you notice and fairly adjust your offer in good faith as needed at the end of this checklist.
    • Check that the ports are unclogged, unbent, and working (bring a flash drive to test this and any other peripherals that are a must-use).
    • Check for creakiness,
    • Ask the seller to turn it on. Do they know the login? Treat the Mac as stolen if not and walk away from the deal. Call police when possible.
      • Listen for strange start-up sounds, like fans going haywire or the ka-chink sounds of a failing hard drive.
    • For MacBooks: Have them play some music to check the speakers
    • For MacBooks: Do the FaceTime camera and microphones function?
      • Try calling yourself, or at least open up the FaceTime app as well as microphone settings to check (System Preferences -> Sound -> Input).
    • For MacBooks: type on the keyboard and use the trackpad
      • Are there any sticky keys? These often result from spills and liquid damage is insidious in what else it may have damaged.
      • Does the trackpad click properly?
      • Do the trackpad gestures work?
      • How about the keyboard backlighting?
      • Does the power button sleep the computer?
        • How about the rest of the function keys, like the volume up/down keys?
    • For MacBooks: is the screen functioning properly?
      • Does automatic brightness adjustment (System Preferences -> Dispalys) work? Cover the ambient light sensor with your hand.
      • Do the brightness up/down function keys work?
      • Are there any dead pixels, discolorations, etc.?
        • If there are, ask them why, and what they’re willing to do about it. Now might be a good time to ask for price decrease to offset part of the expected repair costs, for example, based on the estimates the two of you can find online.
  • Check that Find My Mac in iCloud settings (found in System Preferences) is not currently enabled. If it is and the current “owner” cannot disable it, you should assume the Mac is stolen. If there are any seemingly legitimate excuses for this, delay the sale until the concerns are completely resolved.

  • Check the laptop’s serial number. This lets you view warranty status, model information, and more. If you’re being sold a fake (which is more common with iPhones than Macs), you’ll find out there, as the Mac simply won’t be listed altogether.

  • Check that there is no firmware password set. You can check this by trying to enter Recovery Mode (Cmd + R during boot-up). Here it’s more plausible that they’ve forgotten the password, but they need to go into an Apple Store with an original receipt to have it disabled. Insist that they do so, and not you, as the receipt they’re proferring could be a forged one. Once the firmware password is disabled, meet up again, re-run through the items on this page and ask for that receipt as part of the sale.

  • Check that hardware diagonistics reports no issues. If any do appear, delay the sale, and have the results looked over by an Apple Store Genius. Unless the issues are false positives or definitely repairable at a known, fixed cost, politely call off the sale. Having diagnostics give anything less than an all-clear is the equivalent of multiple warning lights for a car’s dashboard but with greater urgency.

  • At this point, the Mac should be good-to-go. Ask them to reformat it, leaving it fresh and ready for you.

  • Finally, take a (geo-tagged) picture together, write up a receipt for this particular sale, have both of you sign it, and check each other’s IDs. Send copies of the above to each other’s emails. You are establishing the written and photographic record, making any fraud harder to get away with. Remind them of this but also thank them for being willing to go along with your precautions. Both parties should leave feeling that the deal was legal, mutually beneficial, transparent, and fair.

  • Enjoy your new Mac!