One of the most common symptoms of physical damage is that the SD card is not detected by the device it is inserted into. This can be caused by a number of things, including a damaged controller, a damaged NAND, a damaged PCB, and more. On a computer, if the card is not showing in Disk Management (Windows) / Disk Utility (OSX) / Disks (Linux) as a device with the right capacity, we will need to take the SD card apart and access it using specialized hardware.

Such is a hazard of the job for SD cards — being entrusted with some of the most risk-prone hardware often leads to severe damage like bending or breaking. In these cases, we would open the SD card to see if the NAND / monolith is still intact. If it is cracked, there is nothing we can do. With discrete cards having small separated components and monoliths only occupying a small portion of the area inside the card, there is a decent chance that critical components are intact.

This is probably the most common type of failure with SD cards. While they are designed to be resistant to physical damage, they are not designed to last forever. NAND memory has a limited number of read/write cycles before it fails, and this degradation over time is known as wear. The NAND found in SD cards is not as high quality as the NAND found in SSDs, the over-provisioning is not as high, and the controller is not as clever, so wear tends to happen faster for them. In the best of cases, a SD card will become read-only when a certain wear threshold is met to prevent data loss. In the worst of cases, the card will fail spontaneously. In these cases, bypassing the controller to read the NAND directly is the best if not only option.

Discrete design SD cards are not very resistant to water damage. They are not designed to be waterproof, and they are not designed to be resistant to water intrusion. Monolithic SD cards are much more resistant to water damage, but they are not always waterproof either. Salt water is by and large the most damaging of the options. In the case of water damage, the first step is to clean the card and remove any corrosion. This is done with a combination of manual and ultrasonic cleaning. Ideally, the card will be readable after that. If not, we will need to take the card apart and read the NAND directly.

On most devices, if a drive does not contain a known file system, you will be prompted to format it. If the device is *supposed* to have a known file system and has worked previously, something is wrong. This can be a symptom of many different issues, but in the best of cases it’s purely logical — if the card is present in Disk Management (Windows) / Disk Management (OSX) / Disks (Linux) with the right capacity, then there is a good chance we can make a clone from the sd card and repair and / or recover the file system using proprietary data recovery software.

SD cards have a structure called a “translator” that translates the logical addresses requested by the connected device to the physical addresses on the NAND. While formatting a device *usually* is done by simply erasing the file system, a special kind of format can be done that erases the translator as well. This type of format is most often done by Sony cameras, but it is not unique to them. Recovery in this case is done by chip-of methods.

When a device suddenly shuts off mid-recording, the file system is often left in a damaged state; cutting off a delayed write to the file system’s journal / FAT / MFT / etc. will often damage it, and that damage will lead to the drive becoming inaccessible. The file being recorded may be in various states of recoverability — if it was never written to the storage at all (just stored in RAM), it is gone. If it was written to the storage in chunks (caching), it may be partially recoverable although this is highly dependent on the situation. If it was successfully written to the storage but the file system became damaged, it is most likely recoverable.

File recovery and file repair are generally considered entirely different fields, but we can and do try to repair them. The first and most important step is to recover as much of the file data as possible from the media, and that’s where we specialize. For a repair attempt, we do need the card itself to ensure the best possible starting data to work with. If we don’t have the original source, chances of success are less.