You need to format the disk in drive E: before you can use it. In nine out of every ten cases when you see this sentence, the card isn't empty; there is some form of damage to the index (or catalogue) which has caused the issue. The memory card contains two different types of information: your photographs, stored as one continuous string across the flash memory, and a very small database located at the beginning of the card that describes exactly where on the card each file starts and ends. Once that database becomes damaged, your camera will no longer be able to read through all the files, and therefore it will simply offer to do the only thing it knows to fix it: format the card. The pictures themselves have not shifted a byte.
The index gets damaged for dull, mechanical causes. Cards pulled from the body when the write light is on. Battery failure during a burst. Cards used in one body with firmware A and another body with firmware B. Counterfeit cards claiming to be larger than their actual internal flash storage can hold (they work until you reach the true size, then lose everything past it). Plain old wear, since flash memory cells are limited by how many times they can be written, and a card that has been through four winters of wildlife photography will have used up a great many of those writes.
SanDisk is the brand name that turns up most on this bench, simply because SanDisk sells by far the most. Extreme (and Extreme Pro) cards are what most of the working photographers up here shoot with, and they are good cards. But volume means volume, and it also brings some SanDisk-specific issues to be aware of.
First: none of SanDisk's own utilities are data recovery tools. The SD Memory Card Formatter, or any routine that a manufacturer provides as a "format", will do exactly what the name says it does. Format a corrupt card and you will be destroying the very structures a data recovery works from. RescuePRO, which comes with some cards, is a file-carving utility for healthy cards with deleted files. If pointed at a fading card it will just keep a dying controller alive. Second: fake SanDisk cards are everywhere, and a fake Extreme Pro bought cheaply online is the number one source of a card corrupting a shoot with no obvious cause. Third: when a SanDisk card dies completely (no detection anywhere, on any reader), the failure is usually the controller, not the memory. The memory can be read directly past the dead controller. This is a bench job, not a software one, but there is a real way back from this and it works on cards that have been refused by every computer in the house.
Do these, in this order, then stop. Take the card out of the camera and read it through a standalone card reader. Use a good quality card reader as opposed to your camera, to avoid additional layers of interpretation from the camera's software. Try a second reader on a second computer. If using a full size SD card make sure the slide switch for write protection is not down (this is an extremely common error, and an entirely harmless one). Look at the contact points for signs of corrosion or bent pins; also look for hairline cracks near the notch in the plastic.
Then stop. Don't format. Don't run chkdsk or scan-and-fix. Don't allow the camera's card repair to repair your memory card. And don't take another shot with it: each new photo you take will be written into the same space where all of the previous photos are stored. Decline if Windows prompts you to repair errors. Decline if macOS prompts you to initialise. The card can still be read at a level beneath its file system, and this is where a recovery will work from. Every repair tool works above that level and writes as it goes.
A card that won't format is typically in a hardware read-only state; the flash controller has entered a protective mode because it can no longer manage the wear-levelling behind the scenes. Although this sounds like a dead card, cards that are locked in read-only can still be imaged, and imaging a card is exactly what you need for a recovery. The other reason a card won't format is a controller that is beginning to fail, where the card will enumerate briefly and then disappear, or simply not show up on your computer at all. This type of failure is read at the chip level, bypassing the controller altogether.
Whichever of the two it is, the process for recovering the data is the same. The card is scanned sector-by-sector as a read-only device in order to capture an image of the data. Nothing is ever written back to the original card. The file system is then reconstructed using this image, if its records survive. If not, the photographs are extracted based on their header signature (RAW images, JPEGs and video all contain recognisable headers) and then opened and rendered prior to anyone making a claim to recover the photographs, because a file with a name and a size that won't display is not a recovered photograph. Fragmentation can cause problems when trying to recover video and it's worth being honest about that: still photos tend to be much easier to recover than long-form videos.
A large share of the cards being processed through this bench are coming from photographers, and the north-east presents its own particular challenges. Cards swapped with cold fingers on a hill in the Cairngorms get pushed in askew and the contact points suffer. When you take a camera out of the freezing cold (minus five outside) and put it straight into your warm car, condensation forms within the camera itself as well as on your lens. Salt spray along the coast at Fowlsheugh or Troup Head will find every crevice, and a card that has been in a bag on a boat has endured far more than it would appear.
The issue isn't about spending money on expensive memory cards, but about developing habits. Use your camera's format settings instead of your computer's. Get into the habit of doing this before every shoot instead of after. Never completely fill up a memory card. Set a time frame to retire a memory card instead of just letting it go until it fails, because they always fail on the day that matters. At the end of each shoot day, no matter how tired you are, make sure to back up your photos, because the shoot you can never recreate is the one you'll lose. If your memory card is already bad, the diagnostic here costs nothing and is finished within 2 working days from the moment it arrives, and you'll have one fixed written price before anybody touches it.
Hold one line and the shoot will usually survive. This error indicates that there's a problem with the index on your card. Your images are safely sitting on the card behind this index issue. They remain recoverable until something else (formatting, a repair utility or a fresh frame) writes to your card and wipes these photos away. Pull the card out of the camera, place it into its protective case, and don't touch it again until it can be imaged properly.
The diagnosis is free and takes 2 working days once your disk arrives at our premises. The figure quoted is fixed and given to you in writing, and on logical work, in most cases you only pay if we recover your data. Begin online today or call us.