Symptoms
- 'You need to format the disk before you can use it' popup
- Card was working fine before being removed unsafely or a device crashed
- Files were visible before but now the whole card seems empty
- Card capacity shows as 0 bytes used and available
Likely causes
- CommonFile system corruption from unsafe removalPulling the card out while a device was still writing to it can corrupt its index.
- PossibleCard was used across multiple incompatible devices or formatsSwitching file systems between devices can confuse the card's table.
- PossibleDeveloping bad sectors on the cardCheaper or older cards wear out and develop errors over heavy use.
What to do
- Do not click Format yet, since this can make the original files harder to recover.
- Try the card in a different reader or device to rule out a reader-specific glitch.
- Use file recovery software to scan the card and check whether files are still visible.
- Copy anything recoverable to a computer or other drive immediately.
- Once files are safely copied elsewhere, format the card to restore normal use.
- If recovery software finds nothing at all, the card's memory chip may be physically damaged.
Tools and parts
- File recovery software
When to call a pro
If the card holds irreplaceable photos or video and recovery software can't read it, a data recovery lab can sometimes still retrieve files directly from the memory chip.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.