If you have the firmware code, there is a way to clear this (mother f'ing) non-functional "Your Computer is Disabled" count down screen loop. Either take your laptop and proof of purchase to an Apple store or try the following:
I will attempt here to create a Step by Step. You will need two USB sticks.
1] On one stick create a mac OS installer using DiskMaker X (I tried it first with a High Sierra version and it did not boot all the way. Then I tried an older one I had with El Capitan on it and it worked) You will need to google DiskMaker X and learn how to make this needed USB stick. You have to do this on a second Mac. If you can't get El Capitan try it with a newer OS ... maybe I made a mistake the first time in all the steps with the High Sierra version. [edit] I tried following the steps with my High Sierra USB stick again and it seemed to boot all the way so give that a try first since it is easy to obtain the High Sierra OS.
2] (I did this part on my windows machine) On the second USB stick you create a bootable USB with rEFInd boot software . At this web site http://www.rodsbooks.com/refind/getting.html download the "A CD-R image file", not the USB version. This is an ISO file. Next you need a USB maker, I used Universal-USB-Installer-1.9.7.7.exe which I downloaded from Cnet Downloads. Run the USB installer, at the main window for Step 1 there is a drop down menu with lots of Linux choices, scroll to the bottom and choose "Try unlisted Linux ISO". In Step 2 point to your fEFInd iso file. Then select your usb drive and click Create. During the process the installer said it failed and would not be bootable, but I finished it anyway and the USB fEFInd stick worked.
3] Go back to your Mac, plug in both USB sticks and boot holding the Option key down. Enter your firmware code at the lock screen. Then select the EFI boot USB stick and boot to that. Then using the arrow keys select the mac OS USB installer that you made. (see screen shots below) Once that is highlighted, hit the F2 key. This will give you another boot options menu. Select "Boot macos in Singer User Mode". Your mac will start booting to a terminal or command line window. Wait until it has finished scrolling out many lines of startup data, and you are at a command prompt. Then type in this succession of commands:
nvram -c
nvram -xp
nvram -c
nvram -c
nvram -c
nvram -c
nvram -xp
Yes you need to clear the nvram several times in a row! (nvram -xp just lists what is in nvram)
Then type in exit and wait. The laptop should continue booting in that command window until it switches over to the GUI window and you end up at the general OS Installer window. The installer window for El Capitan and High Sierra have a utilities section and the Firmware Password Utility is included. The window using High Sierra calls it the Startup Security Utility. I opened the utility and turned off the firmware authentication using the code ... [at this point I was totally psyched, as you will be, because I had been working on this for several days, including multiple calls to Apple where they told me I had to come in with my proof of purchase (which I did not have anymore for this 2015 mac passed end of warranty, sokeep your receipts!) if I wanted them to clear the Disabled Computer issue.
4] Next I erased the disk using Disk Utility and did a clean install of the OS. (It occurs to me that many of you may not want to wipe the laptop. In this case skip wiping your disk and try shutting down and removing the USB sticks. Then do a nvram & pram clearing boot as follows:
Shut down your Mac.
Locate the following keys on the keyboard: Command (⌘), Option, P, and R.
Turn on your Mac.
Press and hold the Command-Option-P-R keys immediately after you hear the startup sound.
Hold these keys until the computer restarts and you hear the startup sound for a second time.
(if your laptop does not chime, just hold them down after pressing start as quickly as you can and hold until it seems to reboot again)
Please post to this thread if you can succeed without wiping the hard drive.
Good luck, MTFBWY
rws70
(note these instructions were based on a thread I read here: https://www.ghostlyhaks.com/forum/macbook/555-can-t-unlock-macbook-pro-13-retina-disabled )
Here are some screen shots from the process:
Hello everyone,
Thanks for the solution,
I tried the "Boot macOS in Singer User Mode" option but the terminal codes don't end, it becomes like the screenshot below. Any suggestions to fix it?
