Unable to format Micro SDXC card: "fsync failed: input/output error"

Question

I have a 128GB Micro SDXC I've been using to store music that seems to have died. I noticed it was transferring very slowly or not at all as I was syncing music to it. Running a quick error check didn't find anything wrong with it, and quick formatting it didn't help. I tried doing a more thorough formatting and changing the filesystem to exFAT, but the formatting failed with a nonspecific error message on Windows. When I try formatting it on Windows with the Disks utility, I immediately get this error:

Is there anything else I can try for this card on the command line? It seems like other cards I've used for syncing music (which involves transferring up to a few gigabytes at a time as well as updating existing files) have also run into similar problems. Is this expected? Is it normal for MicroSD cards to fail this quickly? Are certain types of cards more reliable, or is there anything I can do to fry them less often?

Answer 1

SD cards are frighteningly fragile.

Golden Rule: Never use one as the sole location for any data. [This applies to all media, of course, but SD cards just die without warning, making it even more important.]

The first thing to do with any card, especially high storage cards, is to check if they're even real. This article has a list of tools for many platforms to check a card's actual capacity. 11 Freeware To Detect Fake USB Flash Drives, SD Cards And SSD Disk. I have no specific endorsement for any of them, however the macOS app F3 no longer works, since maybe Mojave.

Once you've jumped that hurdle, then all you need to do is be certain to never eject one manually; always dismount it first.
That's about the best you can do - the rest is pure luck.

I used to get through literally thousands of these for work, loading advertising playback devices, so we got pretty cavalier about them. We knew they were the correct size because we were buying them direct from the factory in China, but the fail-rates would have been alarming if any of the data we had on them was in any way important. Our simple test if a card was misbehaving was to try one 'long' format. If that didn't work, or even if it looked too slow, the card went straight in the bin.

There's a good QA here - What can I do if my USB flash drive is write-protected or read-only? - with a work-through, but tbh once a card starts to play up in any way, it's not worth the effort to fight it.

The SD Association recommends their own formatter - https://www.sdcard.org/downloads/formatter/ Win & Mac only - though I don't really know what practical difference it's supposed to make. Pity they don't also make an official capacity tester.