MacBook Pro 2012 not starting up

Hi sreehari2002

I know this is scary for you, but I will try to help, and there are others who know a lot more than me. I will cut and paste the Apple Support steps below, but let me ask you a hard question, do you have a backup? If you do, fantastic. If you don't, don't panic yet, the steps below very well may recover your machine.

from https://support.apple.com/en-us/HT204323

If your Mac starts up to a flashing question mark, but then doesn't continue starting up, try these steps.

1. Turn off your Mac by pressing and holding the power button for a few seconds.
2. Press the power button once to turn your Mac back on. Immediately press and hold the Command and R keys on your keyboard to start your Mac from macOS Recovery. Keep these two keys held down until you see an Apple logo or globe. 
3. If prompted, select a Wi-Fi network to connect to the Internet as part of startup.
4. After the macOS Utilities window appears, choose Startup Disk from the Apple menu.
5. Select your startup disk, then click Restart.

If you don't see your startup disk in the Startup Disk window, close the window and try the next sections of this article.

If you don't see your startup disk

If you don't see your startup disk in the Startup Disk window, use these steps to see if your startup disk needs directory repair.

1. Open Disk Utility from the macOS Utilities window.
2. In the Disk Utility window, select your startup disk (usually named "Macintosh HD") from the left side of the window.
3. Click the First Aid tab.
4. Click the Repair Disk button to verify and repair any issues with your startup disk.
5. After your disk is successfully repaired, quit Disk Utility. 
6. Choose Startup Disk from the Apple menu. Select your startup disk, then click Restart. If you still don't see your Startup Disk, try reinstalling macOS on your startup disk.

If you don't see your built-in startup disk in the Disk Utility window, or if Disk Utility indicates there's a hardware issue, your Mac might need repair. Make an appointment with an Apple Genius or an Apple Authorized Service Provider for more help.

If Disk Utility can't repair your startup disk

If Disk Utility finds issues with your startup disk that it can't repair, you might need to reformat it. You should back up any important data on your startup disk before erasing it. Erasing your startup disk deletes everything stored on it, including items in your home folder like your documents and items on your desktop.

If you don't have a recent backup of personal data that's stored on your startup disk, you can use these steps to try to back up your data to an external drive:

1. Connect an external USB, Thunderbolt, or FireWire drive to your Mac. The drive needs to be the same size or larger than your current startup disk. It also needs to be a drive that you can erase.
2. Use macOS Recovery to erase the external drive, then install macOS onto the external drive. Make sure that you select the external disk as the one you want to erase. Don't select your built-in startup disk, usually named Macintosh HD.
3. After installation is finished, your Mac automatically restarts from the external drive. When Setup Assistant appears, select the option to migrate your data from another disk. Choose your built-in startup disk as the source to migrate your data from. 
4. When migration is done, complete the steps of the setup assistant. After the desktop appears, confirm that your data is present on the external drive.

Now that you've made a backup to an external drive, follow these steps:

1. Use macOS Recovery to erase your built-in startup disk and reinstall macOS. Select the built-in startup disk as the one you want to erase, not the external drive. When installation is finished, your Mac automatically restarts from your built-in startup disk.
2. After you erase your startup disk and reinstall macOS, your Mac automatically restarts and setup assistant appears. To copy your personal data back to your startup disk, select the option in the setup assistant to migrate your data from an existing Time Machine backup or other disk. Choose the external drive as the source to migrate your data from.

If you're unable to erase your startup disk or reinstall macOS, your Mac might need repair. Make an appointment with an Apple Genius or an Apple Authorized Service Provider for more help.

stu m wrote:

Thank you macjack and HWTech. He needs to reformat b/c the partition scheme is wrong. Can he retrieve his data?

Assuming the hard drive or cable is not failing or defective, then possibly yes depending on whether the drive is using APFS or HFS+ and whether the drive is using Filevault. The OP will need to boot from an external macOS boot drive so the OP can have access to a fully functioning OS and third party utilities. If APFS was used on the drive then the OP will need to contact a professional data recovery service since there are no third party utilities available to repair an APFS volume (same thing if the drive is failing).

I would be concerned whether the drive may be failing since I believe it may be possible to boot macOS with an MBR partition since I've seen it mentioned that system firmware updates would be unable to be installed without a GUID partition.

If I was working with this laptop, the first thing I would want to do especially without there being any backups would be to check the health of the drive. If the OP doesn't have a bootable external macOS USB drive, then the next best thing is to create a bootable Knoppix Linux USB drive using Etcher (Mac/Windows/Linux) using another computer. Use Knoppix version 8.2 instead of version 8.6 since the later release tends to be a bit glitchy with the display on some Macs.

Option Boot the Knoppix USB drive and select the orange icon labeled "EFI". It may appear the computer is frozen on the Apple boot picker menu, but give Knoppix time to boot (it is a Mac thing). Once at the Knoppix desktop click on the "Start" menu in the lower left of the Taskbar and navigate to "System Tools --> GSmartControl". Within the GSmartControl app double-click on the MBPro's drive icon which will open up the health report for the drive. Post the whole report here either using the "Additional Text" icon which looks like a piece of paper or by taking a picture of the screen attaching it using the "Image Insertion" icon. IIRC you should be able to connect using WiFi while booted to Knoppix to make it easy to attach the report. There should be a networking icon somewhere on the bottom right of the Taskbar to allow you to select your WiFi network.

To @sreehari2002, what version of macOS was used on this laptop? Your screenshot shows a really old version of Disk Utility so I'm thinking you may have booted into a Lion/Mountain Lion installer in Recovery Mode. Try booting into Internet Recovery Mode using Command + Option + R instead to see if Disk Utility can repair your drive/volume. In theory this should boot into the Catalina installer which would have a more recent version of Disk Utility.

First thing your screenshot shows the internal drive is partitioned as "Master Boot Record" which is not correct for booting a Mac. It should be partitioned as GUID.

Please provide more details on what led up to this moment. What was some of the last things you did?

Did this drive actually boot the computer and then spontaneously stopped booting?

Did you try to upgrade macOS? Swap drives? Run Windows on this computer?

It looks like you may not be booted in Recovery Mode?

About macOS Recovery - Apple Support

Also choose the volume, (the indented icon beneath the one you chose) "Disk 14s1"

Also, try clicking on disk14s1, to see if that gives you the option.

See HWTech's post. You need to reformat the drive for Mac.

I invite other, more knowledgeable people to chime in, but, did you try "Verify Disk?"

Thank you macjack and HWTech. He needs to reformat b/c the partition scheme is wrong. Can he retrieve his data?

Wow. I gave you a "helpful" on that despite most of it being over my head. But I appreciate it greatly as I'm trying to learn. Thanks to your detective work, we learned from the OP that he just upgraded from a 500gb to a 1TB disk, so ostensibly he already has a backup, if he still has the 500gb. Regardless, you solved his problem and I learned something.

Thank you

Good catch HWTech! I didn't notice that.