I built a Raspberry Pi 3 B+ for someone, and it ran fine for several months. The user said they started having problems with it, and had to pull the power to fix it, and that this had happened several times. Eventually it stopped booting. The red LED would light up, but the green one would not, and no image on the screen.
I was able to take a look at it today. I took the MicroCenter 32GB Class 10 SD Card out, used Windows to delete partitions and volumes, used SD Formatter to format it, and Win32DiskImager to write the latest version of Raspbian to the card. Seemed slow, but worked fine. I only watched Win32DiskImager for part of the time, but most of the transfer was ~7mb/sec.
Plugged things back in and had the same problem. Swapped out and disconnected peripherals (as much as possible; had to use an HDMI-VGA adapter, but I did try a spare), and no change.
On a whim, I decided to try another 32 GB Microcenter Class 10 SD card. Worked fine. I only watched Win32DiskImager for part of the time, but most of the transfer was ~33mb/sec.
Is this the "SD Card corruption" issue that I've seen talked about so much online? I would have thought the damage would be irreversible, or that formatting and imaging the card should resuscitate it.