How To Check A Used Mac For Problems

Some people are a little apprehensive when it comes to buying secondhand products, including Mac computers, and it is very much understandable. After all, it’s only normal to express doubts about a product — the use and performance of which you have not personally witnessed or extensively tested. Luckily, for your peace of mind, there are actually plenty of ways to check a secondhand Mac for possible problems before you spend your hard-earned cash on it.

In this tutorial, we will teach you how to:

  1. Check your Mac Package
  2. Check the Exterior of Your Laptop for Visible Problems
  3. Check the Hardware for Possible Internal Problems
    1. Checking the battery
    2. Checking the keyboard
    3. Checking the trackpad
    4. Checking the ports
    5. Checking the webcam
    6. Checking the optical drive
    7. Running the Apple Hardware Test
  4. Checking the Software for Possible Problems
    1. Checking the booting process
    2. Checking for a firmware password
    3. Checking Wi-fi and Bluetooth connectivity
    4. Checking for attached Apple accounts
    5. Checking the password manager


Checking Your Mac Package

Macs come in pretty straightforward packages. Depending on the model of your Mac, the box should come with:


  1. MacBook
  2. 29W USB-C Power Adapter
  3. USB-C Charge Cable (2 m)

MacBook Air

  1. MacBook Air
  2. Power adapter
  3. AC wall plug
  4. Power cord

MacBook Pro

  1. 13-inch MacBook Pro
  2. 61W USB-C Power Adapter
  3. USB-C Charge Cable (2 m)

When the seller hands over the secondhand Mac, make sure that these items are included in the box unless you had a previous agreement to exclude them in the turnover (e.g. seller no longer has them and has offered to deduct the price of the missing item from the total cost). While you’re at it, you may also want to ask your seller for a proof of purchase before you accept the Mac.

Keep in mind that buying stolen goods, regardless whether you were aware that they were stolen or not, could land you in legal trouble (or at best, lead you to getting your Mac confiscated without any compensation), so it’s best to stay on the safe side.

Aside from asking for the receipt, you may also want to compare the serial number printed on the sticker slapped on the box of the secondhand Mac that you are buying with the serial number that you can find on your Mac’s System Information (refer to the instructions below to access it). Inconsistencies between the two may hint at a problem, and you might want to discuss it with your seller before you close the deal.

Verifying your Mac’s Model

Except for the differences in sizes, differentiating MacBook models from one another at a glance might prove to be a bit of a challenge. Since models have slightly varying prices depending on their features, you might want to ensure that you are paying for the right model when you buy your secondhand Mac.

To do this,

  1. Click on the Apple logo at the top-left corner of your screen.
  2. Click on “About This Mac.”
  3. A pop-up box showing your Mac’s model, version, manufacture date, and serial number will appear.
  4. Should you wish to see other hardware information, just click on “System Report.”

Checking the Exterior of your Mac

While the physical appearance of your Mac is typically not as important as the hardware and software installed inside, certain damages to the body of your Mac may be indicative of a more serious internal problem.

For example, a significant dent in your Mac can affect its ability to display images properly, while hearing rattling noises while you are using your Mac or when you give it a little shake may be indicative of a loose component inside that may lead to potential problems like overheating among other things.

Checking the Hardware

After you’ve ensured that all items that come with Macs are accounted for and there is no visible external damage on your laptop, it’s time to check the hardware.

Below is a list of components that you may want to examine if you are buying a secondhand Mac and how you can do it.


Batteries come with predetermined charge cycles. The more your Mac is used and eventually charged, the more charge cycles will be used up. Once your Mac approaches its battery’s maximum charge cycle, degradation in your battery’s performance will become increasingly noticeable. Depending on your Mac’s model, maximum charge cycle may be anywhere between 300 to 1000.

To check how many charge cycles your secondhand Mac has gone through,

  1. Hold the Option key down while clicking the Apple logo.
  2. Select “System Information.”
  3. Choose “Power.”
  4. Look for “Cycle Count.”

Typically, the lower the charge cycle; the better.


Make sure that your keyboard is working properly by opening a document and typing each key.


Check the trackpad and see if it responds when you glide your fingers across it or press on it. You wouldn’t want a trackpad that doesn’t respond to your actions, but you wouldn’t want an overly sensitive trackpad that reacts to the slightest touch and leads to a lot of accidental clicks either.


Ports are important for connecting your Mac to external devices, so take time to check that all ports are functioning as they should. Start with plugging in your USB drive and firewire cables to their respective ports, then follow it with inserting your headphone and microphone jack to check if they can be recognized by your system.


Next, check your Mac’s webcam by opening the Photo Booth app.

To open Photo Booth,

  • Click the “Go” menu from the desktop and select “Applications.”
  • Find “Photo Booth” in the Applications folder, or
  • Click the “Search” button in your menu bar.
  • Type photo booth and press “Return.”

If your webcam is working properly, you should be able to launch the app and have fun with taking test photos. If not, you will see a message that says that Photo Booth cannot detect your camera.

Optical Drive

If your secondhand Mac comes with an optical drive, get a CD or DVD and see if your Mac can open and play it properly.

Running the Apple Hardware Test

If you’ve already done all of the tests above and you’re still feeling a little uneasy or you’re still unsure whether you have missed something or not, you can also run the Apple Hardware Test to check if all installed hardware is working properly. The AHT typically comes pre-installed in newer versions of Macs, and on the recovery discs that come with the computer when it is bought from the store.

To run the AHT,

  1. Disconnect all external devices except the following:
    1. Keyboard
    2. Mouse
    3. Display
    4. Ethernet connection (if applicable)
    5. Connection to AC power
  2. Make sure that your Mac is on a stable and well-ventilated work surface.
  3. Shut down your Mac.
  4. Turn on your Mac, then immediately press and hold the D key on your keyboard.
  5. Keep holding the D key until you see the Apple Hardware Test icon.
  6. Select your language and click the right arrow, then press the “Return” key.
  7. To begin testing, click the Test button, press T, or press “Return.”
  8. You can also select “Perform extended testing” before beginning the test. This will perform a more thorough test but it might take a longer time to complete.
  9. When the test is complete, review your test results in the lower-right section of the window.
  10. To quit Apple Hardware Test, click “Restart” or “Shut Down” at the bottom of the window.



  • If your secondhand Mac came with OS X Lion v10.7 or later, it will start up from AHT over the Internet.
  • If your secondhand Mac came with OS X Lion v10.7 or earlier and you can’t get AHT to start, search for the installation disc marked “Applications Install Disc 2.”
  • Insert the disc in your internal optical drive or external Apple SuperDrive before following the steps above.
  • If your secondhand Mac is a Macbook Air manufactured in late 2010, plug the MacBook Air Software Reinstall thumb drive into your USB port instead.


Checking the Software

After you’re done with checking your secondhand Mac’s hardware, let’s move on to checking the software.

System Boot

Make sure that the system boots properly. You can do this by pressing the power button then waiting for the computer to load the OS installation setup. If the installation setup did not load or won’t continue to the next step, there could be some problem with the hard drive.

Firmware Password

Aside from the login and screensaver password, Macs offer its users an additional layer of security by giving them the option to set a firmware password which they need to put in right after the computer began to boot. This prevents unauthorized users from accessing the laptop by booting from an external drive or using Single User mode to have complete control over the Mac.

While a security feature such as this might be a welcome addition under normal circumstances, forgetting to ask the seller to give you the firmware password or disable it altogether can give you a major headache so don’t forget to ask about it.

Older Mac models may allow you to skip the firmware password by removing the RAM, but the process requires a certain amount of technical knowledge, and is, thus, not recommended for newbies who may inadvertently end up causing damage to the system.

Check the WiFi  & Bluetooth Connectivity

Make sure that your secondhand Mac’s Wi-fi is working properly by scanning list of available networks then connecting to one. Follow it up with checking its Bluetooth by pairing it with another device. If it successfully detected the other device and you were able to transfer a test file, then you are all good.


Check for Attached Apple Accounts

A lot of secondhand Macs come with attached iCloud accounts, and there is inevitably one or two seller who will forget to sign out of their accounts before they sell or give away their Macs, so take it upon yourself to check for any existing Apple accounts before you use your secondhand Mac.

To see if there’s an attached Apple account to your secondhand Mac,

  1. Go to Preferences.
  2. Click iCloud.
  3. See if the previous owner is still signed into their account.
  4. If they are, just sign them out.

Check for Password Managers

In some Mac models, there is a built-in utility tool called Keychain that allows users to save passwords for local applications as well as for the websites that they frequently visit, which may be used to login to certain websites automatically. This is not something that you might want to happen, especially if the previous owner enabled file sharing on your secondhand Mac as it can easily make you vulnerable to identity theft or just good old cyber snooping.

To make sure that you won’t end up sharing sensitive information on your secondhand Mac,

  1. Open the “Utilities” folder in the Applications folder in Finder.
  2. Double-click “Keychain Access.”
  3. Click the lock icon in the top left of the screen.
  4. Enter the user’s login password and click “OK.” If you don’t have the password, you may ask the previous owner
  5. Choose a keychain from the “Keychains” menu.
  6. Look for “Category.”
  7. Choose the category that you want to open.
  8. Right-click on the key that you want to delete and choose “Delete.”
  9. Right-click one of the keychains and click “Delete” if you want to delete a group of keychain at the same time.
  10. To permanently delete keychain information, click on “Delete References and Files.”

That mostly sums up the basics.

If you find the prospect of the task a little unnerving, and you would prefer to have an expert do the checking for you, then it is recommended that you buy your secondhand Mac from an authorized Mac and other Apple product reseller as they usually have an in-house team assigned to help customers with that. Aside from helping you with the checkup, they are also in a good position to answer whatever question may come to your mind while you are examining the computer.



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