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This SSD suddenly refused to boot

I am not worried about data—it's all back up—but I would like to fix the partitions on this 512 GB SSD for mac.

disk util gives this

/dev/disk2 (external, physical):

#: TYPE NAME SIZE IDENTIFIER

0: *512.1 GB disk2

MM2014:~ roberthancock$ sudo gpt -vv -r show /dev/disk2

Password:

gpt show: /dev/disk2: mediasize=512110190592; sectorsize=4096; blocks=125026902

gpt show: /dev/disk2: PMBR at sector 0

start size index contents

0 1 PMBR

1 125026901

MM2014:~ roberthancock$

Can someone help with a possible command line fix?

Posted on Apr 30, 2021 5:30 PM

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2 replies

May 3, 2021 6:54 PM in response to Barney-15E

Thank you for replying. It was a fully functioning Mac boot drive that suddenly refused to boot. Now, when I put it on another Mac, although it mounts on the Desktop very slowly after several minutes, it can neither be erased nor partitioned in any form. Inspecting it with the Mac app called testdisk shows it to be read only! testdisk can see two HFS+ partitions one of which is marked * indicating it is the boot partition, but neither of them can be manipulated in the app. I think it has "lost" its partition map in sector 0.

I think the overprovisioning has been fully used in re-allocating damaged sectors which has forced the firmware to read-only. In this state, it seems like nothing can "touch" the drive!

I tried the Crucial Executive software tool on a windows machine but since the drive appears to be uninitialized, the Crucial tool can't touch it either.

Barney-15E

Level 10

116,686 points

May 3, 2021 6:45 PM in response to Robert Hancock3

It appears it is not formatted.

You may have to erase it and restore from your backup.

In Disk Utility, select Show All Devices in the View popup menu.

Erase the drive as APFS with GUID Partition Map

This SSD suddenly refused to boot