MacBook Pro 2015 Can't Boot Up, Reinstall OS, Erase Hard Disk, or Restore from Time Machine Backup

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Level 1

4 points

MacBook Pro 2015 Can't Boot Up, Reinstall OS, Erase Hard Disk, or Restore from Time Machine Backup

This is related to a thread on this forum from last year that was never resolved but became inactive.

I woke up one morning to find that my Macbook Pro screen was showing a question mark on the screen. Resetting the NVRAM did not help.

When I tried to boot into macOS Recovery, it automatically switched to the Internet Recovery. From here, I have tried using Disk Utility to (1) verify, (2) repair, (3) re-partition, or (4) erase the hard disk, and none of these are successful.

Verifying the disk results in the messages "Problems were found with the partition map which might prevent booting" and "Error: Couldn't mount disk"
Repairing the disk results in the messages "Problems were encountered during repair of the partition map" and "Error: Partition map repair failed while adjusting structures to fit current whole disk size"
Re-partitioning or erasing the disk result in similar messages like "Error: -69760: Unable to write to the last block of the device" for erasing the disk and "Error: -69874: Couldn't modify partition map" when erasing the main volume. This happens regardless of which format I choose when erasing or partitioning, and whether I use the GUI or terminal.

When I boot into diagnostic mode and the diagnostics run (also through the internet mode), it says "There may be an issue with a storage device. Reference Code: VDH002).

After all of the above options failed, I tried restoring from my Time Machine backup, but it did not accept my password, which I'm quite sure is correct (this may be related to the issue mentioned on this forum, where someone has noted that sometimes the correct password is not accepted in Recovery Mode but is accepted in the migration wizard when installing the OS from scratch).

Finally, I tried reinstalling the OS, but when I'm prompted to choose which disk to install the OS on, there are no disks to choose from.

Pictures of my attempts to use Disk Utility from terminal are attached below:

MacBook Pro 13″, macOS 11.2

Posted on Jun 8, 2021 9:18 AM

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Answer 1

kpg7 Author

Level 1

4 points

Jun 12, 2021 11:55 AM in response to HWTech

My laptop was running macOS 11.2 before these issues started happening, so it's not an old version.

Unfortunately, your suggestion of writing zeros didn't work (see picture).

I'm interested in resetting the hardware to factory defaults using the Linux boot disk and utility. I already have a Linux boot flash drive, so could you provide instructions for doing the reset?

I think it's very likely that the hard drive is failing. As I indicated in my original post, I tried all of the partitioning and formatting options available in disk utility, and none of them worked.

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Answer 2

HWTech

Level 9

60,800 points

Jun 12, 2021 9:27 AM in response to kpg7

That looks like a really old version of macOS you show in your pictures since the output of the drives do not show "Internal" or "External" or "Physical" or "Virtual". Sometimes macOS and Disk Utility can get confused by some partition structures and file systems. Try writing zeroes to the beginning of the SSD by using this command (I'm assuming the physical drive is still "disk1" so make sure to change it if it is different next time).

Make sure to disconnect all external drives so that you don't accidentally destroy the data on the wrong drive.

First unmount all volumes on the physical SSD:

diskutil  unmountDisk  disk1

Next write zeroes to the very beginning of the SSD:

sudo  dd  if=/dev/zero  of=/dev/disk1  bs=100m  count=10

Now try to erase the SSD normally. If it still does not work, then the only other suggestion I have is to try resetting the SSD to factory defaults using the SSD's built-in hardware secure erase feature (if this SSD supports it). However, this requires a Linux boot disk and utility. I can provide instructions if you are interested.

It is also possible the SSD is failing. Some types of SSD failures can be fixed by resetting the SSD to factory default using the Linux utility I mentioned. I have done so on a few Apple SSDs.

Also I didn't have time to look at the "diskutil" command to know what default file system is being used when erasing the SSD with the command you show in your picture. Make sure the SSD is partitioned and formatted as GUID partition and MacOS Extended (Journaled) or HFS+ (Journaled).

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Answer 3

Jun 12, 2021 3:55 PM in response to kpg7

I think in this case, disk1 would be the recoveryOS image. For obvious reasons that can't be erased.

Try writing zeroes to disk0.

If you want to be sure which identifier is associated with the internal drive, run "diskutil list" (without the quotes).

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Answer 4

HWTech

Level 9

60,800 points

Jun 13, 2021 4:05 PM in response to kpg7

kpg7 wrote:

I already did "diskutil list", as shown in the screenshot on my original post. disk1 was the correct one to use.

The order of the drives/volumes can change between reboots. You always need to check and verify the current correct drive identifiers. The "dd" command requires all volumes to first be unmounted which is why you could not write zeroes to the SSD. Double check you are trying to unmount the correct device first.

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