How to recover files from a corrupted or damaged SD card, USB drive, or memory card

Summary

This guide helps you troubleshoot and resolve: How to recover files from a corrupted or damaged SD card, USB drive, or memory card. Follow the steps below to fix the issue.

Common Causes

SD cards, USB drives, and memory cards can become corrupted due to improper ejection, power interruptions, file system errors, physical damage, or malware. When this happens, your files may appear missing, inaccessible, or the device may prompt you to format it. This guide walks you through practical methods to recover your data using built-in operating system tools and reputable third-party recovery software before considering a format or replacement.

Before You Begin: Important Precautions

Taking the right steps at the start can make the difference between successful recovery and permanent data loss.

• Stop using the device immediately. Any new data written to the card or drive can overwrite the files you're trying to recover.
• Do not format the device if Windows, macOS, or the device itself prompts you to. Formatting erases the file system and dramatically reduces recovery chances.
• Avoid removing the card or drive while data is being accessed. Always use the safe eject procedure before unplugging.
• Recover files to a different storage location than the source device. Saving recovered files back to the same corrupted card can cause overwriting.
• Check for physical damage. If the card or USB connector is bent, cracked, or visibly damaged, recovery software will not help. Skip to the end of this guide for hardware recovery options.

Method 1: Check the Connection and Try a Different Reader

Sometimes the issue is not the card itself but how it is being read.

1. Remove the SD card or USB drive and inspect the contacts for dust, lint, or corrosion. Gently clean the gold contacts with a soft, dry cloth or a cotton bud lightly dampened with isopropyl alcohol.
2. Reinsert the device firmly into the original port.
3. If the device is still not recognised, try a different USB port or a different card reader. Built-in laptop readers can fail independently of the card.
4. Test the card on a different computer. If it works elsewhere, the original machine may have a driver or port issue rather than a card problem.

Method 2: Use Built-In Repair Tools

Both Windows and macOS include tools that can repair common file system errors without erasing data.

Windows: Run CHKDSK and the Error Checking Tool

1. Connect the SD card or USB drive and note the drive letter assigned in File Explorer (for example, E:).
2. Press Win + X and select Terminal (Admin) or Windows PowerShell (Admin).
3. Type the following command, replacing E: with your drive letter, then press Enter:
   chkdsk E: /f /r /x
4. Wait for the scan to complete. The /f flag fixes file system errors, /r locates bad sectors and recovers readable information, and /x forces the drive to dismount first.
5. When finished, open File Explorer and check whether your files are accessible.

Alternatively, you can use the graphical error checker:

1. Open File Explorer, right-click the drive, and select Properties.
2. Click the Tools tab.
3. Under Error checking, click Check.
4. Select Scan and repair drive and follow the prompts.

macOS: Use First Aid in Disk Utility

1. Connect the SD card or USB drive to your Mac.
2. Open Disk Utility from Applications > Utilities, or search for it using Spotlight (Cmd + Space).
3. Select the affected device in the sidebar. If you see multiple entries, choose the one representing the volume rather than the physical device.
4. Click First Aid in the toolbar, then click Run.
5. When the repair completes, click Done and check whether the volume mounts and your files appear.

Method 3: Recover Files Using Recovery Software

If the built-in tools cannot repair the file system but the device is still recognised by your computer, recovery software can scan the raw storage and reconstruct files. Below are three reputable options that work on both Windows and macOS.

• Recuva (Windows, free for personal use) — straightforward interface, good for USB drives and SD cards.
• PhotoRec (Windows, macOS, Linux, free and open source) — recovers a wide range of file types including documents, photos, and videos.
• TestDisk (Windows, macOS, Linux, free and open source) — more advanced, can also rebuild damaged partition tables.

Example: Recovering Files with PhotoRec

1. Download PhotoRec from the official CGSecurity website and extract the folder.
2. Connect the corrupted SD card or USB drive.
3. Open the extracted folder and run photorec_win.exe (Windows) or photorec (macOS/Linux terminal).
4. Select the affected drive from the list using the arrow keys, then choose Proceed.
5. Select the partition type. For SD cards and USB drives, choose No partition or Whole disk if the partition table is damaged.
6. Choose a filesystem. Select FAT/NTFS/ext for most SD cards and USB drives, or Other for exFAT.
7. Select a destination folder to save recovered files. This must be on a different drive than the one being recovered.
8. Press Y to start the scan. PhotoRec will recover files into numbered folders in the destination you selected.
9. Once complete, browse the recovered folders and copy any files you need back to your normal storage location.

Method 4: Recover Files from a Card That Will Not Mount

If your computer does not assign a drive letter or the card does not appear in Disk Utility, the partition table may be damaged. TestDisk is particularly effective in this scenario.

1. Download and extract TestDisk from the CGSecurity website.
2. Run testdisk_win.exe (Windows) or testdisk from a terminal on macOS/Linux.
3. Select Create to make a new log file, then choose the affected drive.
4. Select the partition table type. For SD cards and most USB drives, this is usually Intel or EFI GPT. TestDisk can often detect the correct type automatically.
5. Choose Analyse, then Quick Search. If the partition is not found, run Deeper Search.
6. When the partition appears, highlight it and press P to list files. You can copy individual files or entire folders to another location.
7. Press Q to quit when you have finished copying files.

Method 5: When Software Recovery Is Not Enough

If none of the methods above restore your files, the device may have a hardware fault. At this point, further software attempts risk making the situation worse.

• Professional data recovery services use specialised equipment to read damaged flash memory directly from the chip. This is the safest option for physically damaged cards or drives.
• Manufacturer warranty replacement may be available if the device is still under warranty, although this typically replaces the hardware rather than recovering the data.
• Retire the device once recovery is complete or attempted. A card or drive that has corrupted once is more likely to fail again, so it is best replaced.

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