Recovering Data from a Failing SSD on a Mac
The first move you make when an SSD starts failing often determines whether your data survives.
Symptoms of a dying SSD include slow file copies, beachballs that never end, files that vanish and reappear, and First Aid errors in Disk Utility. If you see any of these, stop using the machine for normal work.
Every additional hour of normal use can push a fading drive past the point of recovery. Boot into Recovery, then use Disk Utility to create a disk image of the failing volume to a healthy external drive. Work from the image, not the original.
Do not run cleanup utilities, do not reinstall macOS, and do not 'try a few more reboots.' These are the most common ways I see clients lose data permanently before calling for help.
If the drive won't mount at all, the next step is specialized recovery hardware. I keep a small recovery rig in the truck and can attempt block-level imaging on-site. For severe physical failure, I refer to a clean-room lab and coordinate the handoff.
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