image by: Alejandro Escamilla (

5 Things to check before buying second hand Macbook

Christian Kanzie Nilsson
The Brave New World
7 min readJan 7, 2016


This Christmas my sister wanted to buy a used Apple Macbook. They are famous for high second hand value and rightly so. A Mac with a few years on it usually is still a very competent computer and the build quality is bar none. I was tasked with picking up the computer.

I met with the sellers of the Macbook and did what most buyers of second hand equipment do, I judged the people. Problem is, I’m not buying them! I’m buying something that they dearly want to get rid of. Most often so on false pretenses.

I checked what I could while standing in their kitchen with the sellers nervously hovering behind my back.

  • Is the disk wiped
  • Do all keys on keyboard work
  • Is everything in the box present
  • Do they have the original box
  • Does it look used/abused

While these are all good things to check there are better ways to know if you are buying a lemon or not. Since I didn't know these things at the time I paid and wrapped it in Christmas paper.

I bought a dud!

It didn’t take long after unwrapping it before we realized something was wrong though. It got me thinking

“What can a presumed buyer of Apple hardware do to increase insight of the units actual condition?”

Surely there must be more I can do than check the keys on the keyboard? I remember when I worked in a Apple store a few years back that we had testing applications we could run on customers laptops before doing service. Something like that would have been very useful even though Im not a expert service technician. I started reading up on what steps I could have taken and decided to compile a list for you all to use as reference.

1: Check actual age of the machine

The age of the machine is not when the seller bought it. It is whatever Apple say it is. Macbooks are built in generations, usually twice per year. Even though there is no new announcement or changes of price, you and your friend who bought the exact same Macbook only 10 months apart can have quite different machines.

Open the lid of the Macbook, press the Apple in top-left corner and click “About this Mac”. From there a new window shows up which in newer machines show the Serial Number, in older machines you have to double-click on the version number. (

You can also turn the machine up-side-down as the serial number is printed on the bottom.

Copy or write this number down. Then visit Apples Warranty Checker online by going to this URL: It will tell you the model and in parenthesis which revision the Macbook is. For example “MacBook Pro (Retina, Mid 2012)”.

This page also tells you current warranty coverage situation and gives you the actual name to search for when you want to find out specifics about this particular model and revision.

2: Require proof of purchase

This goes without saying but if you have bought something as pricey as a new computer you tend to know where the receipt is. If bought online there is a digital copy stored on your account. When the seller “have lost it” you know something is up.

3: Check how much is left of battery

Now this is a important one. No battery lasts forever and as a matter of fact laptop batteries in general is not very long-lasting. Specially not considering the latest trend of not making them replaceable without serious breach of warranty. It is not impossible, you can still get the battery replaced by authorized Apple stores for a cost of around $200 (excluding taxes) but this is an extra cost to factor in.

A Lithium-Ion battery which is what Apple uses counts load cycles. The battery can take about 1000 load cycles with progressively worse performance. You can check health and how many load cycles the battery has by holding option-key down while clicking the Apple logo in top left corner and select System Information. In the new window choose “Power” and look for Cycle Count. You want this to be a value less than 500. Over 500 load cycles and you will be experiencing a battery that quickly drains and before not too long will require constant power cable.

Apple claim that below 1000 cycles is good but my experience is different. You can find official information about maximum load cycles here (

4: Confirm all keys are functional

Open the lid and find anywhere you can type, like the password box or so but even better a box where you can see the letters printed. Then progressively press each key on the keyboard and make sure something comes up on the screen at the same time you press the key. Also make sure it has a solid “bump” as you press the key down since dirt under the keys can be very expensive to get out and shows extreme wear from previous owner.

The Apple keyboard and touchpad are exceptional and they should never have any quirky feeling to them. If in doubt pass up on the buy. A bad keyboard will drive you mad over time. Replacing these is expensive and buying extra keyboard defeats the purpose of a laptop.

Make sure you test Space and arrow keys as these are more exposed and more common problem keys than the rest of them for some reason. Ensure the Space key works evenly across the whole key, not just center.

5: Run Apples built-in hardware test “AHT”

This is by far the most important thing. Built in to every Macbook there is a stand-alone hardware testing application that is very advanced, yet simple to run. It doesn't care what the shady seller is saying, nor does it try to pretend being better than what it is. It will take a long (anywhere between 15 mintues to upper extremes of an hour), hard look at itself and tell you exactly how it is feeling and if anything is bad or broken.

It doesn't just report what is broken, but also gives you health indicators on what the wear and tear components of the computer such as the disk drive (yes, even SSD wear out) and battery.

To start the test software follow these steps:

  1. Shut down your computer. Then, press the power button to turn it back on.
  2. Press and hold the D key before the gray startup screen appears.
  3. It takes a minute or so for AHT to start up and inspect your hardware configuration. When finished loading select language and then click the “Test”-button.

The extended test is more thorough and a bit overkill for just checking the computer but if you want to overkill the check then do click it. Prepare a cup of coffee though as it takes an hour to complete. I recommend the basic test. Read more at Apple website:

Running the test can take a while but it is insignificant amount of time given the amount of dough you are handing over the compared to the time you will regret the purchase if you buy a broken machine.

Bonus: Check for dead pixels

This is the most common thing people mention when you ask for advice but honestly not very important. The idea is that all thin monitors well wear out and this happens pixel by pixel. The higher quality of screen, the longer it will last but there are lemons everywhere. A dead pixel is not always a black dot on the screen which is what you might think. Instead it can also be a shining bright pixel which is how a pixel “dies”. It is not always easy to spot and most screens have somewhere between zer0 and ten of them randomly placed on the screen somewhere.

Try to find a dark background or object on the screen you can move around and then search for a white pixel on the screen. Do the opposite for black pixles. If you see more than 10 of these I would avoid the computer, less than that though is reasonable if not in a terrible place (read: middle of screen). There are blogs talking about how to fix some problems with dead pixels but really just accept that this is inevitable and not a huge deal.

Hope you enjoyed this article and please let me know if it saves you in any future purchases. Please press the heart below to recommend it to others.



Christian Kanzie Nilsson
The Brave New World

Christian is a tech trend scout, a passionate software architect & wannabe author.