A hosiery workshop in Anstey had a knitting machine dropping stitches in a pattern nobody could describe over the telephone, so they filmed it running and sent the clip to the manufacturer's engineer. The card then began showing an error in the camera, and on the workshop laptop it did not appear at all. The engineer's visit was booked for the following week and the video was the only record of a fault that only shows itself every few hours.
| Media | A Samsung SD card holding one video recording made in a workshop. The camera now reports an error when the card is inserted and the card does not appear at all on a laptop. |
| What was reported | Samsung SD card, shows an error in the camera it was recorded on, does not appear on a laptop at all, a single video wanted off it, needed before an engineer's visit the following week. |
| Fault class | Logical. The card's memory answered normally on a controlled reader and the recording was present. What had failed was the small structure describing the volume, which the camera reads as an error and the laptop cannot interpret well enough to offer a drive letter for. |
| On the bench | Read behind a hardware write blocker so that neither a camera nor an operating system could write to it; imaged read-only through a controlled reader in a single pass with no unstable regions found; the surviving directory entries parsed from the image in R-Studio; the recording rebuilt from its allocation chain where the chain held and continued forward through the image where it did not, with each block confirmed as belonging to the same stream; the result played from beginning to end before being written to fresh media. |
Two different failures on two devices is one fault in the card. A camera checks the volume in its own limited way and reports an error when the check fails. A laptop tries harder, gets less far, and quietly offers nothing. Both are downstream of the same damaged structure, and the difference between the two symptoms is only the difference between how much each device attempts before it gives up.
An error message is not a report on the recording. Cameras have almost no vocabulary for this. Card error covers a damaged volume, a worn card, a card the camera does not recognise and a card that has been removed mid-write, and the same three words appear for all of them. Nothing in that message says anything about whether the video is still in the memory, and in this case all of it was.
Reformatting is the instruction the camera will offer, and it is the wrong one. The camera's remedy for a volume it cannot read is to write a fresh one, which is quick, effective and permanent. On a card holding one irreplaceable recording it is the most expensive button available. The workshop had been told by somebody that formatting fixes cards, which is true in the sense that it makes them usable again and false in every sense that mattered here.
Video is the format where guessing goes wrong. A long recording is written across the card in whatever order space came free, and a tool that finds the start of a clip and estimates the end will usually produce something that plays for thirty seconds and then stops. Following the allocation chain, and where it breaks, confirming each block belongs to the same stream, gives back the recording rather than an opening fragment of it.
The card was write-blocked before anything read it, and it then read at full speed on a controlled reader with no weak regions and no reallocation. That settled the important question early: the memory was healthy and this was a structure problem rather than a worn card.
R-Studio found the directory damaged but not gone. The record for the video survived with its start and the first part of its chain, and the remainder was resolved by walking forward through the image and checking each block against the stream. The rebuilt file was played from beginning to end at full length before anything was called finished, since a clip that plays for a few seconds and stops is a common and useless result.
The whole recording came back, including the four minutes at the end where the machine actually dropped the stitch, which was the part that mattered. It went out in a second format as well, so that the manufacturer's engineer could open it without needing anything unusual installed.
Cards and sticks are £250 + VAT. The fault was logical throughout, with nothing opened and no chip lifted, so no fix, no fee applied and the invoice followed once the workshop had watched the clip. The card was not returned to service.
Take the card out and leave it out. Do not accept the camera's offer to format it, and do not put it back in to see whether the error has cleared, because a camera that manages to mount a damaged volume may well write to it. On the computer side, refuse any prompt to repair or initialise, and do not run a recovery tool that saves its output to the card it is reading. If the recording is the only copy of something with a date attached to it, that is worth saying when you send it in, since a job with a fixed deadline is scheduled differently from one without. Post it in something rigid rather than loose in an envelope, and mention which camera made the recording, because the way a file is laid down varies between makes and it changes where the bench starts.
Each of these is a real enquiry, taken from a household or a business somewhere in Leicester or the surrounding county, with the name of the customer, the firm and anything else that would identify them taken out. What is left is the reasoning: what turned up, what had actually failed inside it, the method that fault required and the equipment it was worked on. One of the thirty-six is a job that was refused, and it belongs here every bit as much as the successes do.
A file that appears in a scan has not gone anywhere; the index that lists it has
A card that reads as empty has lost its list, not its contents
A card has nothing moving inside it, so a fall damages the way in rather than the contents
Examining it is free and takes 2 working days from arrival, the figure goes to you in writing and does not move afterwards, and a logical fault carries no fix, no fee. Start online or ring the freephone.