SD card not reading?
Your photos and videos are most likely still there
The camera says "Memory card error," the dash cam keeps asking to format, and your Mac can't read the card either. Don't format it in the camera yet. Often only the card's file system records are damaged, and the photos and videos themselves are still there.
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It may not be the card at all
Write-protect switch
When the small switch on the side of the SD card is set to Lock, the card is read-only. That won't make it unreadable, but it can make the camera show an error.
Card readers and adapters
Try another card reader or your Mac's built-in SD card slot; poor contact in microSD adapters is common.
Cards used in a Raspberry Pi or Linux device
If you see only a boot partition, it's because the other partition is Ext4; see the Raspberry Pi SD card guide.
Don't format it in the camera or dash cam
Formatting wipes the directory records. Get your photos and videos off first, then format the card and keep using it.
Common situations, and what can be done today
| Recoverable | Notes | |
|---|---|---|
| Power lost or card removed while recording, now asks to format | ✓ | exFAT / FAT32 records weren't fully written; opened read-only |
| Card reads very slowly, or imports fail partway | ✓ | Image it first, then find files in the image |
| Raspberry Pi or Linux device cards | ✓ | Ext4 partition; CrossDriver Ext4 also works |
| Photos were deleted | Not yet supported | Needs a deep scan |
| Card already formatted in the camera | Not yet supported | Needs a deep scan |
| No computer detects it | — | Usually the card itself has failed; take it to a professional |
If power was lost while a video was being recorded, that last clip may never have been fully written; other files are usually unaffected.
Read an SD card on a Mac with NAS Rescue
It has NAS in the name, but it works just as well on a single USB stick, external drive, or SD card: connect it, scan, preview for free, and recover once you see your files.
- 1
Insert the SD card
When you see "The disk you attached was not readable by this computer," click "Ignore."
- 2
Select and scan
Open NAS Rescue, select the card, and click "Scan Disks." If the card reads very slowly, check its health first and image it when prompted.
- 3
Preview
Browse DCIM and other folders, and open photos and videos for free to make sure they're all there.
- 4
Recovery
After upgrading to Pro, copy them to your Mac or another disk with shooting dates (file modification dates) preserved, each one verified with SHA-256.
Q&A
My SD card won't read and says it needs to be formatted. Can the photos be recovered?
Usually, yes. As long as you haven't formatted it, scan read-only first. If the card opens, you'll see the photos and videos in DCIM; preview them for free, then copy them out.
Can photos deleted in the camera be recovered?
Not with NAS Rescue yet. Recovering deleted photos, or photos from a formatted card, needs a deep scan, which isn't supported yet. Until then, don't shoot or write anything else to the card.
My Mac's built-in SD slot can't read the card. Will a different card reader help?
Sometimes. Try another reader to rule out a contact problem; if the card still won't read, scan it read-only using the steps above.
My dash cam keeps asking to format the card. What should I do?
Dash cams record in a constant loop, which wears cards out quickly. Copy the videos you need first, then format. If it keeps happening, switch to a high-endurance card.
Related products and guides
CrossDriver NAS Rescue
SD cards, USB sticks, external drives, and NAS drives: scan read-only and preview for free before recovering.
Read and edit a Raspberry Pi SD card on Mac
Open a Raspberry Pi SD card's rootfs (Ext4) on a Mac.
USB drive says it needs to be formatted
When a USB drive asks to be formatted, don't click yet.
If you haven't formatted it, your photos still have a chance
Download NAS Rescue and check for free whether the photos and videos on your card are still there.
Download for Mac — Free Scan & Preview