Mac Aht Download

Mac Aht Download

I recently had a problem with the battery in my Macbook Air. I was following the instructions provided by Apple, but when pressing the D key upon startup, I was still being booted into Mac OS X instead of the hardware diagnostics.

The knowledge base had no solution for me but, after some looking around, I found the problem.

I have a 1.25Gb iMac 20' G4 that originally shipped with OSX 10.3 back in 2004. I must have inadvertently discarded the install disc which contained the Apple Hardware Test. I am trying to locate a copy of the AHT that I can burn onto a CD. Oddly, when I attempt to download the AHT from Apple's website, all that I get is the Read Me file. Apple Service Diagnostic Disks 25 GB Original Applications: Mac: English: ASD Dual Boot 2.1.5 (2003) PowerBook G4 (12-inch), PowerBook G4 (17-inch), iMac (17-inch 1GHz), Power Mac G4 (FW 800), Xserve (slot load), eMac (ATI Graphics), and Power Mac G4 (Mirrored Drive Doors 2003), iMac (USB 2.0), PowerBook G4 (15-inch FW800), PowerBook G4 (17-inch 1.33GHz) and PowerBook G4 (12-inch DVD).

Your Mac will not boot into diagnostics if you have a firmware password set. In order to run the Apple Hardware Test, you’ll need to temporarily disable your firmware password. Here’s how you do it.

Are you not sure if this is what’s causing the problem? Luckily, this is easy to check.

  1. Shut down your Mac (Apple -> Shut Down…)
  2. Locate the Option key on your keyboard
  3. Press the Power button and then immediately press and hold the Option key

You will now either see a screen with two hard disk images (your disk and a recovery disk), or a large lock icon with a password entry. If you see the password entry, this is issue preventing you from loading the Apple Hardware Test.

Since you’ve determined that you have a firmware password, we’ll need to temporarily disable it.

Mac Aht Download
  1. Follow the steps above (Shut Down, Hold Option until you see the password entry)
  2. Enter the firmware password
  3. Select the recovery disk using the arrow keys and enter
  4. Click Utilities -> Firmware Password Utility
  5. Click “Turn off firmware password”
  6. Enter the previous firmware password
  7. Shut down your Mac (Apple -> Shut Down…)

Now you should be good-to-go! Follow the instructions provided by Apple and run the tests. Remember to reset your firmware password when you’re done.

Check compatibility

Mac Aht Download Pc

You can upgrade to OS Yosemite on any of the following Mac models. Your Mac also needs at least 2GB of memory and 8GB of available storage space.

MacBook introduced in 2009 or later, plus MacBook (13-inch, Aluminum, Late 2008)
MacBook Air introduced in late 2008 or later
MacBook Pro introduced in mid 2007 or later
Mac mini introduced in early 2009 or later
iMac introduced in mid 2007 or later
Mac Pro introduced in early 2008 or later
Xserve models introduced in early 2009

To find your Mac model, memory, storage space, and macOS version, choose About This Mac from the Apple menu . If your Mac isn't compatible with OS X Yosemite, the installer will let you know.

Make a backup

Before installing any upgrade, it’s a good idea to back up your Mac. Time Machine makes it simple, and other backup methods are also available. Learn how to back up your Mac.

Get connected

It takes time to download and install OS X, so make sure that you have a reliable Internet connection. If you're using a Mac notebook computer, plug it into AC power.

Download OS X Yosemite

For the strongest security and latest features, find out whether you can upgrade to macOS Catalina, the latest version of macOS.


If you still need OS X Yosemite, use this link: Download OS X Yosemite. A file named InstallMacOSX.dmg will download to your Mac.

Install the macOS installer


Double-click the downloaded file to open a window showing its contents. Then double-click the file within, named InstallMacOSX.pkg.

Follow the onscreen instructions, which will guide you through the steps necessary to install.

Begin installation

After installation of the installer is complete, open the Applications folder on your Mac, then double-click the file named Install OS X Yosemite.

Mac Aht Download Software

Click Continue and follow the onscreen instructions. You might find it easiest to begin installation in the evening so that it can complete overnight, if needed.

Allow installation to complete

Please allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac might restart, show a progress bar, or show a blank screen several times as it installs both OS X and related updates to your Mac firmware.

Learn more

Mac Aht Download Windows 10

  • OS X Yosemite won't install on top of a later version of macOS, but you can erase your disk first or install on another disk.
  • You can use macOS Recovery to reinstall macOS.