SD Card or USB Drive Not Readable? Do This First

Flash media such as SD cards, microSD cards and USB sticks are used everywhere and are often the only place where photos, video and documents are stored. When one becomes unreadable, the cause could be a damaged file system, a worn or failing memory chip, or a physical problem with the connector or the board. Which one it is decides what can be done.

If a card or stick is behaving strangely, stop using it at once. Do not take more photos, do not save anything to it, and do not let the camera or phone reformat it. New data can overwrite files that would otherwise be recoverable. This is especially important after photos have been deleted by mistake or the card has been formatted in the camera.

A message to format the disk before use, a RAW file system, or a size shown as 0 bytes usually means the file system structures are damaged. The data may still be present. An error about a card that is write-protected, or a card that is detected but has no capacity, can point to a failing controller or worn memory. A card that is not detected at all can be a dirty or bent connector, a bad reader or cable, or a failed device.

Try a different card reader or USB port, and try another computer. Clean the contacts gently with a dry, soft cloth. Check whether the card has a physical lock switch. If the card appears but cannot be read, do not accept the format prompt and do not run a repair. If it opens, copy the files you need to a different drive right away, starting with the most important ones.

Do not format the card to see whether that fixes it. Do not run a disk check or repair on a card you want to recover from. Do not keep re-inserting a card that is hot, very slow or repeatedly disconnecting, because that can be a sign of failing memory. Do not install recovery software onto the same card, and do not recover files back onto it.

Cards and sticks that are bent, cracked, have been through water or have a broken connector may need work on the board or on the memory chips themselves. Many modern USB sticks and microSD cards keep the controller and memory in one sealed unit, which makes this harder, and success cannot be assumed. Do not try to dry a wet device with heat and do not attempt to open it.

After a quick format or deleted photos, files can often be found by reading the card and reconstructing them from what remains, although names and folders may be lost. The chance is best when the card has not been used since. A full format, or heavy reuse afterwards, lowers the chance. Working from an image of the card keeps the original safe from further changes.

Ask a specialist when the data is irreplaceable, such as photos from an event that cannot be repeated, when the device is not detected, when it is physically damaged, or when your own attempts have not worked. We have solved many cases like this, and we tell you what is recoverable after a free assessment. Afterwards, keep a second copy of anything that matters, since flash media can fail without warning.