Corrupting the SD card doesn’t happen in isolation. If your SD card is asking you to format, has empty folders, or is spitting out random names on filenames, you’ve taken the wrong road and need to know what the road was so you can determine if the SD card is worth saving and how you’re going to save it. First we’ll identify the cause of corruption; next will be rescuing the data from the corrupt SD Card, then the repair. Once we get through the steps in this guide, if it’s just the files that were damaged instead of the entire SD Card itself, our corrupted file recovery service will take over.
The most common reasons for corruption come down to: (1) interrupted writes, (2) moving your SD card from device to device, (3) counterfeited capacity, and (4) worn out flash. None of these are inherently fatal and no matter what road your SD card took to get here, if you catch the problem soon enough, you won’t have to throw away those photos.
Interrupted writes are the first way. For example, if a card is removed (or a battery dies) before the camera’s buffer is completely flushed to the storage media. When this happens, the file system is left “mid-sentence” so to speak, and will therefore be unable to parse subsequent “insertions.” Although less common than interruption, another method by which damage can occur is Device-hopping, the switching of devices. This would involve transferring the card from a camera, through a phone, and on to a computer, and then finally to an HDTV or other display device. Each of these devices have their own views as to what format the file system should take, and thus create their own thumbnail files, indexes etc., until there exists an area where two or more of the above created files conflict. Counterfeit capacity is the third and perhaps most devastating way of damaging photographs, i.e., purchasing a card that claims to hold 256 GB, however in reality only holds far less. Until you reach the point of filling up the actual amount of space available on such a card, it appears to function normally. However once this limit is reached, it will begin to silently overwrite previous photographs and also will corrupt data wholesale. It is worth noting that counterfeit cards often come from marketplace sellers who sell them at prices significantly lower than those of reputable vendors. Lastly, damage can occur simply due to plain wear of flash memory. Budget-grade memory chips used in cheaper cards have shorter write lives than do higher quality memory chips used in professional grade cards. Over time (as would be expected), one of the chips on your card will start to mis-remember the photographs previously stored on it. All of these roads arrive at the same place, which is why the rescue is the same for all of them.
If the card is showing signs of corruption (every time you add data it will be written over previous photos’ last known address), stop using the card immediately. Get a computer card reader for the card (using the camera as a cable is slower and less reliable) and decline all prompts offered by the OS (Format, Scan & Fix, Initialise etc) and run PhotoRec: completely free, completely read-only and designed to extract images, movies and other pictures directly from the flash memory regardless of if they are listed in the file system. Set PhotoRec’s output folder on the PC, NOT ON THE CARD, and check your results by viewing the recovered files, starting with the largest first. Spending just ten minutes doing this will recover nearly all corrupted-card cases and cost you nothing.
The only exception where the above won’t work: when the card isn’t recognised at all, when it overheats or physically rattles. This is typically due to faulty hardware such as a failed controller or more serious issues. At this point there is little that can be done with home tools; monolith-level reads performed on a bench are required. We offer a free diagnostic, which also represents the beginning of our memory card recovery service, in both cases.
Once you have verified that the photos were successfully saved to your computer you can deal with the card fairly. Reformatting the entire card in the device it will live in will recreate all structures on the card and most likely restore function to the card. However, there is one rule of thumb: “two strikes”. Corruption that occurs without any apparent reason (i.e. no yanking the card, no dead battery) usually indicates that the flash memory itself is failing and once a card fails twice, you know how it intends to continue. Cards cost pounds and you cannot reshoot a christening, so suspect cards should be retired, new branded ones purchased from reputable dealers, reformatted in the device rather than under Windows and treated like couriers rather than archives; photos should be removed from it in less than a week. Reformatted the card before reading this and then recalled what was on it? Use the same extraction methods but go here instead: formatted media recovery.
No, this is the complete opposite of “healing” from a bad write. Cards that will eventually read after multiple attempts (i.e., work in the camera but not the computer, or vice versa) are experiencing deterioration of their controllers or contact pins with each successive attempt. Each time you retry, you’re giving a half-written (and therefore possibly corrupted) data set another opportunity to become even more corrupted. First-time corruption should be viewed as your memory card’s “resignation letter.” Remove the images immediately and remove the card from service.
Repeat corruption nearly all of the time has some identifiable source. There are generally four sources for this type of corruption: the card moves between different systems which each have their own way to handle file systems; the card is pulled from the device or the battery dies before the write operation completes; the card is counterfeit and therefore the labelled storage size is more than actual (corrupts everything stored beyond the “real” full limit); or the flash memory is simply old. Genuine branded cards used by an end user in the system they were originally intended to be formatted in; then removed after all writing is complete; will rarely repeat itself.
Do NOT run CHKDSK until all photos have been safely copied off the failed media. CHKDSK will repair the file structure of a memory card by writing corrections to the file system; however, it has the unfortunate side effect of converting severely damaged files into worthless FILE0000.CHK fragments, and has resulted in the loss of many photo collections. Therefore, the only safe course of action is to copy all photos off the card with a read-only utility, and then allow CHKDSK or a format to rebuild the remainder of the media.
A free 48 hour diagnostic will provide you with an honest assessment of what occurred to your SD card as well as if attempting to carve out files yourself will be possible without risking further damage prior to utilising our memory card recovery services.