My SD card suddenly became corrupted and is no longer readable by my phone or computer. It contains important photos and files that I haven’t backed up. What’s the safest way to recover data from a corrupted SD card without losing or overwriting anything?
Don’t format the card or run CHKDSK/“repair” tools first, since they can overwrite recoverable data. Stop using it, remove it from the phone, and use a reliable USB card reader to create a full sector-by-sector image with a tool such as GNU ddrescue. Run recovery software against that image, not the original card, and save recovered files to a different drive. If the card disconnects repeatedly, gets hot, or shows the wrong capacity, stop and consider a professional recovery service because that points to hardware failure.
Don’t keep testing the card in different phones and readers. Every power cycle can make a failing card worse. If the files are truly irreplaceable, skip DIY recovery and get a professional assessment. If they aren’t worth that cost, follow @silentforge2620’s imaging advice, but set a strict limit: if imaging produces repeated errors or disconnects, stop rather than hammering the card for hours.
Don’t assume the card itself is dead just because Windows asks to format it. A bad microSD-to-SD adapter or cheap reader can produce the same symptoms. Trying one known-good reader is reasonable; cycling through every device in the house is not.
There are really two different jobs here: repairing the file system and recovering the files. Repair tools try to make the card usable again, while recovery tools look for data even when the file system is broken. Since your photos matter more than making the card work, recovery should come first. The imaging approach @silentforge2620 described gives you a safe copy to work from.
When scanning the image, start with a normal file-system scan because that has the best chance of preserving folders and filenames. A deeper “raw” or signature scan may find more photos, but often returns thousands of generically named files with missing dates and duplicates. Save everything to another drive, check that the recovered photos actually open, and only then consider formatting or replacing the card. Even if it becomes readable again, I wouldn’t trust that card with anything important.
A perfect recovery is not guaranteed, even if software can see the card. File names, folder structure, timestamps, and partially overwritten photos may be lost, so the realistic goal is to retrieve as much intact content as possible without making the situation worse.
Before scanning anything, check how the phone used the card. If Android formatted it as “internal storage” or enabled SD-card encryption, the data may be tied to that specific phone and its encryption keys. In that case, ordinary photo-recovery tools can find blocks of data but cannot turn them into usable files. Do not factory-reset the phone, remove its lock settings, or discard it while recovery is pending. A card configured as normal “portable storage” is much more straightforward.
The computer’s exact response matters too. If Disk Management shows the card at roughly the correct capacity, even with an unknown or RAW file system, software recovery is worth attempting. If it shows 0 bytes, “no media,” or a wildly incorrect size, that is usually beyond what file-recovery software can address. Repeated disconnects are another reason to stop, as @binaryhub1259 said.
Once you have a sector image, keep the first successful image untouched and scan a copy of it. That prevents a recovery program, accidental mount, or repair attempt from changing your only good capture. Free tools such as TestDisk can look for lost partitions and damaged file-system structures, while PhotoRec can carve photos and other known file types when the directory information is gone. The latter is useful, but expect generic filenames, duplicates, thumbnails, and files that appear recovered but do not fully open.
Plan storage space before starting. A 256 GB card needs about 256 GB just for the image, plus room for a working copy and recovered files. Put all of that on a healthy drive, never back onto the SD card. Afterward, verify important photos at full size rather than trusting previews, since a damaged JPEG can still produce a valid thumbnail. Regardless of the result, retire the card instead of formatting it and putting it back into service.
ddrescue isn’t really a Windows tool, so heads up if that’s your setup. You’ll want a Linux boot USB or a Linux box to run it properly, otherwise people burn hours trying to get it working before they even touch the card.