Fix it
Memory Card Errors, Slowness or Corruption? Fixes (2027)
Fix camera memory card problems: card errors, slow-card warnings, buffer stalls, corrupt files and suspected counterfeits.
A card error message mid-shoot feels catastrophic, but the disciplined response - stop, swap, protect the suspect card, diagnose at home - saves both the shoot and usually the files. Work through these fixes in order and never format a card you still need data from.
Camera shows card error or cannot use this card
Power off, reseat the card, and clean contacts gently with a dry microfibre cloth. Try the card in a reader: if it mounts, copy everything immediately, then format it in the camera and test with a burst before trusting it again. A card that errors twice is retired, no debate.
Slow card warnings and dropped video frames
Your sustained write is below the codec's demand: the card may be a lower class than its label, nearly full, fragmented, or counterfeit. Format in-camera, test the mode again, and verify the card with a sustained-write benchmark. Replace with a genuine V60 or V90 from an authorised seller if the warning persists.
Buffer stalls during stills bursts
Confirm you are not asking a UHS-I card to clear flagship RAW bursts: the bus, not the brand, is the ceiling. Move to UHS-II in both slots (a slow second card can bottleneck mirrored writing), shorten burst discipline, and check that image review and clarity processing settings are not adding write load.
Files appear corrupt or a card reports the wrong capacity
Stop writing to the card immediately - every new file overwrites recoverable data. Image it with recovery software such as the makers' bundled tools, then run a full-write capacity test. Wrong real capacity confirms a counterfeit: document it, claim through the seller, and treat it as a lesson in channel discipline.
Questions, answered
Can corrupt card photos be recovered?
Often, yes, if you stop using the card at once. Recovery software reads surviving file structures; continued shooting is what makes corruption permanent.
Why is my fast card slow in my reader?
The chain is card, reader bus, cable and port. A UHS-II card in a UHS-I reader, or a charge-only USB cable, silently halves or quarters offload speed. Match every link.
Should I delete photos in-camera to free space?
Prefer swapping cards and formatting after backup. Mass in-camera deletion fragments the file system and invites the slow-card behaviour you are trying to avoid.