Windows – MicroSD card is not detected by Windows

You might have a defective card reader. Try another one.

If that doesn't work, the card may very well be bad and the data on it unrecoverable. Restore your data from backup on a new card.

You could try pressing the card together (in case it came a little loose?) and maybe cleaning the contacts with a little bit of isopropanol on a swab. But I really wouldn't expect any results, and at best you might manage to read some of the data off before it dies again. I would not recommend opening it up under any circumstances - that will not help recovery any, and it will likely cause further damage.

You could also try various alternative readers - if you manage to find one that can at least expose the card as a block device, then you can take an image of the data (while recovering useful data from an image of damaged media is a whole other exercise - it's still better than where you are now).

Sometimes, there just isn't anything that can be done. If the data is very important, you could consider professional data recovery services (do they even exist for SD cards?), but they'd be very expensive. Otherwise, she might just have to accept the loss and try to recreate what she can.

When a storage device becomes physically unreadable, undetectable even, you can't go through the normal home data recovery steps (take image, scan for what files you can, etc.). With a mechanical drive, at least common failure modes are partial, so you can at least read something. With the nature of NAND storage, I can think of three possibilities:

• You've lost the controller. The flash chip itself might still be readable, but reassembling the data from it will be a long and arduous task. This is not doable at home, and requires expensive, professional tools and expertise. (If you had the equipment to solder tiny chips ^(source) and read NAND flash, I suppose you could attempt this yourself, but you're more likely to accidentally destroy it.)

• You've lost the flash chip itself. In this case, I don't think there's anything you or anyone else can do. It would be even harder to recover than a lost controller.

• The card is physically damaged, but the controller and flash memory are intact. This is probably the best you can hope for. Again, with how small and fragile the card is, there isn't much you can do at home - but the chance of professional recovery is far higher.

The problem with all these is they require very expensive and still uncertain services to even attempt a recovery. Is the data worth that much?

Perhaps the best thing to do is to treat this as a lesson on backups - always have at least one extra copy of any data you can't afford to lose. The more important it is, the more copies you want, stored separately from each other.