Make sure the format is "Mac OS Extended (Journaled)" and click ERASE. Click the ERASE button and give your drive a name "Macintosh HD" is the standard name that's used. Select the drive itself and not any of the volumes that may be listed under the drive. You should see your hard drive listed on the left side of the window under the category of "Internal". When the Disk Utility window appears, in the upper-left corner of the window is a VIEW button. This will launch Disk Utility and allow you to reformat your drive. Select the bottom option ("Disk Utility") and click CONTINUE. The computer should do a network boot from a Catalina installer on one of Apple's internet NetBoot servers.Įventually - it could take awhile - you should see a "macOS Utilities" window appear with four options.
Release the keys, then select a wireless network and enter the network password if applicable. You should see a spinning globe icon and a drop-down menu that allows you to select a wireless network. Immediately after the second startup chime hold down COMMAND-OPTION-R. (Think of this as resetting the BIOS to factory defaults.)
This will "zap the PRAM" and while not technically required for this process it will reset some settings to give you a cleaner experience. Continue holding down those keys until you hear the startup chime twice. Power on the computer while holding down SHIFT-COMMAND-P-R. Starting with the computer off, plugged in to AC power, and assuming there is no firmware password. Here's the process I would recommend to you. (Think "firmware password" as "BIOS password".) If your Mac has a firmware password, however, you will need that password. If you intend on wiping the drive and starting fresh, no, you do not need a pre-existing admin password. According to the holy grail of guides you can run pretty much anything up to the most current version of OS X which is 10.15 or "Catalina". A1502 marks your laptop as a Late 2013, Mid 2014, or Early 2015.