データを失うことなく破損したSDカードを修復する方法

2025年9月1日
データを失うことなく破損したSDカードを修正する方法

A 破損したSDカード can make your photos, videos, documents, or camera files suddenly inaccessible. You may see an error message saying the card needs to be formatted, the SD card may not show up on your computer, or some files may disappear without warning. When this happens, the most important rule is simple: do not format the SD card immediately. Formatting may make the card usable again, but it can also make it harder to recover lost files on the SD card. If the corrupted SD card contains important data, recover or back up your files first, then try safe repair methods.

This guide explains how to fix a corrupted SD card and how to recover data from a corrupted SD card with a dedicated data recovery software like Magic Data Recovery.

Magic Data Recoveryをダウンロード

Windows 7/8/10/11およびWindows Serverをサポート

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Quick Answer: What Should You Do First?

If your SD card is corrupted, follow these steps in order:

  1. すぐにSDカードの使用を中止してください。.
  2. Do not save new files to the card.
  3. Do not format the card before recovering important data.
  4. Try another card reader, USB port, or device.
  5. Recover files from the corrupted SD card with data recovery software.
  6. After recovery, repair the card using チェックディスク, Windows Error Checking, Disk Utility First Aid, driver repair, or formatting.

If the SD card is physically damaged, cracked, bent, burned, water-damaged, or not detected by any device, stop DIY repair and consider professional data recovery service.

Common Signs of a Corrupted SD Card

An SD card may be corrupted if you notice one or more of the following symptoms:

症状

What It Means

Recommended First Step

SD card asks to be formatted

File system may be damaged

最初にデータを復元する

SD card is not detected

Connection, driver, or card issue

Try another reader or device

ファイルが消える

File system error or hidden files

Scan the card and show hidden files

SD card becomes RAW

File system is unreadable

Recover data before formatting

Photos or videos cannot open

File corruption or bad sectors

Recover and check file integrity

SD card shows wrong capacity

Partition or controller issue

カードの使用を停止する

Read/write error appears

Card may be locked, failing, or corrupted

Check lock switch and repair errors

Camera says “Card error”

File system incompatibility or corruption

Recover files, then format in camera

These symptoms do not always mean the card is permanently broken. In many cases, a corrupted SD card can still be repaired, especially if the problem is caused by ファイルシステムエラー, improper removal, interrupted transfer, driver issues, or malware.

What Causes an SD Card to Become Corrupted?

Understanding the cause can help you choose the right repair method. Common causes include:

1. Removing the SD Card Improperly

If you pull out the SD card while files are being copied, deleted, or saved, the file system may become incomplete or damaged. This often happens when removing a card from a camera, phone, drone, dash cam, or computer without ejecting it safely.

2. Interrupted File Transfer

A sudden power loss, low camera battery, app crash, or system freeze during file transfer may leave the SD card in an unstable state.

3.ファイルシステムのエラー

The SD card uses a file system such as FAT32 or exFAT to organize files. If the file system is damaged, your device may no longer be able to read the files correctly.

4. Virus or Malware Infection

If the SD card is connected to an infected computer, malware may hide, delete, encrypt, or damage files.

5.バッドセクター

After long-term use, some storage blocks on an SD card may become unreliable. This can cause file access errors, slow loading, or repeated corruption.

6. Physical Damage

Bending, cracking, water exposure, heat, dust, or damaged metal contacts can prevent the SD card from working properly.

7. Using the Same Card Across Many Devices

Switching the same SD card between cameras, phones, drones, dash cams, and computers may increase the risk of compatibility errors, especially if different devices use different file system rules.

Before You Fix a Corrupted SD Card: Important Safety Tips

Before trying any repair method, follow these safety rules to avoid permanent data loss.

Do Not Format the SD Card First

Many devices will show a message like:

  • “「使用する前にディスクをフォーマットする必要があります。”
  • “SD card is damaged. Try reformatting it.”
  • “Card error.”
  • “「ボリュームには認識されたファイルシステムが含まれていません。”

Do not click Format if the card contains important data. Formatting can erase file system records and reduce the chance of successful recovery.

SDカードの使用を中止してください

Do not take new photos, record new videos, download new files, or run repeated repair attempts on the card. New data may overwrite deleted or inaccessible files.

信頼できるカードリーダーを使う

Sometimes the SD card is not actually corrupted. The problem may come from a faulty card reader, USB port, adapter, or cable. Always test the card with another reader before assuming the card is damaged.

重要なファイルを最初に復元する

If the files are important, recover them before running repair commands or formatting. Some repair operations may modify the file system, which can make recovery more difficult.

How to Recover Data from a Corrupted SD Card

If your corrupted SD card is still detected by Windows, you can try recovering files with Magic Data Recovery before repairing or formatting the card.

Magic Data Recovery can help recover files from SD cards, microSD cards, memory cards, USB drives, external drives, and other storage devices. It is especially useful when files are deleted, lost, inaccessible, or missing because of corruption, formatting, or file system errors.

Important: Do not install the recovery software on the corrupted SD card. Do not save recovered files back to the same SD card. Always save recovered files to another drive.

Step 1: Connect the Corrupted SD Card to Your Computer

Insert the SD card into a card reader and connect it to your Windows computer. If you are using a microSD card, use a reliable microSD adapter or card reader.

Make sure Windows can detect the card. Even if the card is not accessible in File Explorer, it may still appear in Disk Management.

ステップ2：Magic Data Recoveryのダウンロードとインストール

Download and install Magic Data Recovery on your computer. Install it on your computer’s internal drive, not on the corrupted SD card.

Magic Data Recoveryをダウンロード

Windows 7/8/10/11およびWindows Serverをサポート

Step 3: Select the Corrupted SD Card

Launch Magic Data Recovery. In the main interface, select the corrupted SD card or memory card as the target drive.

Magic Data Recoveryを実行し、失われた上書きファイルを検索する。

Step 4: Scan the SD Card

Start scanning the corrupted SD card. The scan time depends on the capacity of the card, connection speed, card condition, and number of files.

For example, a 32GB SD card may scan faster than a 256GB SD card. If the card has many bad sectors, scanning may take longer.

失われたデータの検索

Step 5: Preview and Select Files

After the scan, preview recoverable files if available. Select the photos, videos, documents, audio files, or other data you want to recover.

プレビューファイル

ステップ6：ファイルを別のドライブに復元する

Click Recover and choose a safe location on another drive. Do not save the recovered files to the corrupted SD card.

回復した上書きファイルを保存する
After recovery is complete, open the recovered files and check whether they are usable. Once your important files are safely recovered, you can move on to repairing the corrupted SD card.

How to Fix a Corrupted SD Card Without Formatting

Method 1: Try Another Card Reader, USB Port, or Device

Before running repair commands, rule out connection problems.

When to use this method

Use this method if:

  • The SD card is not showing up.
  • The computer does not detect the card.
  • The SD card disconnects randomly.
  • The card works on one device but not another.

やり方

  1. Remove the SD card from the current device.
  2. Insert it into another card reader.
  3. Try a different USB port.
  4. Test it on another computer.
  5. If it is a camera or phone SD card, insert it back into the original device and check whether it is detected.

If the card works with another reader, your original card reader or adapter may be faulty.

Method 2: Check the SD Card Lock Switch

Full-size SD cards usually have a small lock switch on the side. If the switch is in the locked position, the card may become write-protected.

When to use this method

Use this method if:

  • You cannot copy files to the SD card.
  • You cannot delete files from the SD card.
  • Windows says the disk is write-protected.
  • Formatting fails because the card is locked.

やり方

  1. Remove the SD card.
  2. Check the small switch on the side.
  3. Slide it to the unlocked position.
  4. Reinsert the card into your computer.
  5. Try accessing the files again.

If the lock switch is loose or broken, try using another adapter for microSD cards.

Method 3: Assign a New Drive Letter on Windows

Sometimes an SD card is detected by Windows but does not appear in File Explorer because it has no drive letter or has a conflicting drive letter.

When to use this method

Use this method if:

  • The SD card appears in Disk Management.
  • The SD card does not appear in File Explorer.
  • ドライブレターがない。.
  • Another device uses the same drive letter.

How to assign a new drive letter

  1. Right-click Start.
  2. Select Disk Management.
  3. Find your SD card.
  4. Right-click the SD card partition.
  5. Select Change Drive Letter and Paths.
  6. Click Add or Change.
  7. Choose a new drive letter.
  8. OKをクリックする。.

After assigning a new drive letter, open File Explorer and check whether the SD card is accessible.

assigni a drive letter to fix corrupted SD card

Method 4: Use Windows Error Checking

Windows includes a built-in error-checking tool that can scan and repair file system errors.

When to use this method

Use this method if:

  • The SD card is visible in File Explorer.
  • You can right-click the card.
  • Windows can access the drive properties.
  • The card has minor file system errors.

How to use Windows Error Checking

  1. Connect the SD card to your computer.
  2. Open This PC.
  3. Right-click the SD card.
  4. プロパティを選択する。.
  5. Go to the Tools tab.
  6. Under Error checking, click Check.
  7. Follow the on-screen instructions to scan and repair the card.

If Windows finds errors, allow it to repair them. After the process finishes, reopen the SD card and check your files.

Method 5: Fix a Corrupted SD Card with CHKDSK

CHKDSK is a Windows command-line tool that checks a drive for file system errors and attempts to repair them.

Warning: CHKDSK may modify the file system. If the SD card contains important files, recover your data first.

When to use this method

Use CHKDSK if:

  • The SD card has file system errors.
  • Windows asks you to scan and repair the drive.
  • Files or folders are inaccessible.
  • The card is detected but not working correctly.

How to run CHKDSK

  1. Connect the SD card to your computer.
  2. Note the drive letter of the SD card, such as E: or F:.
  3. Type cmd in the Windows search bar.
  4. Right-click Command Prompt.
  5. Choose Run as administrator.
  6. 次のコマンドを入力します： chkdsk G: /f

Replace G: with your SD card drive letter.

  1. エンターキーを押す。.
  2. Wait for the process to finish.
  3. Reopen the SD card and check whether it works.

You can also use: chkdsk E: /f /r

について /f parameter fixes file system errors. The /r parameter locates bad sectors and attempts to recover readable information. The /r scan may take longer.

Using CHKDSK to fix a corrupted SD card

Method 6: Reinstall or Update the SD Card Driver

A corrupted, outdated, or unstable driver may prevent Windows from reading your SD card properly.

When to use this method

Use this method if:

  • The SD card is not detected.
  • Device Manager shows an error.
  • The card reader stops working after a system update.
  • Other USB storage devices work, but the SD card does not.

How to reinstall the SD card driver

  1. Right-click Start.
  2. Select Device Manager.
  3. Expand Disk drives or Universal Serial Bus controllers.
  4. Find your SD card or card reader.
  5. Right-click it and select Uninstall device.
  6. Disconnect the SD card.
  7. コンピュータを再起動してください。.
  8. Reconnect the SD card.

Windows will reinstall the driver automatically. After that, check whether the card appears in File Explorer or Disk Management.

Method 7: Remove Write Protection with DiskPart

If the SD card is write-protected, you may not be able to format it, delete files, or repair it.

When to use this method

Use this method if:

  • Windows says the disk is write-protected.
  • You cannot save files to the SD card.
  • You cannot delete files from the card.
  • The physical lock switch is already unlocked.

How to remove write protection

  1. Connect the SD card to your computer.
  2. コマンドプロンプトを管理者として開く。.
  3. タイプ ディスクパーツ
  4. タイプ リストディスク
  5. Identify your SD card by size.
  6. タイプ ディスクXを選択

Replace X with the disk number of your SD card.

  1. タイプ 属性 ディスククリア 読み取り専用
  2. タイプ 出口

After clearing read-only status, try accessing or repairing the SD card again.

Be careful when using DiskPart. Selecting the wrong disk may affect another drive.

Method 8: Show Hidden Files on the SD Card

Sometimes files are not lost but hidden by system settings, malware, or file attribute changes.

When to use this method

Use this method if:

  • The SD card opens but files are missing.
  • Used space shows that files still exist.
  • Folders appear empty.
  • Files disappeared after connecting to another computer.

How to show hidden files on Windows

  1. ファイルエクスプローラを開く。.
  2. SanDiskドライブを選択します。.
  3. Select Show.
  4. 「表示」をクリックします。.
  5. SDカードをもう一度開いてください。.

You can also use Command Prompt: attrib -h -r -s /s /d E:\*.*

Replace E: with your SD card drive letter.

This command removes hidden, read-only, and system attributes from files and folders on the SD card.

How to Fix a Corrupted SD Card by Formatting

If none of the above methods work, formatting may be the final option. フォーマット can rebuild the file system and make the card usable again.

However, formatting erases data. Recover important files before formatting.

Format a Corrupted SD Card on Windows

  1. Connect the SD card to your computer.
  2. Open This PC.
  3. Right-click the SD card.
  4. Select Format.
  5. Choose a file system:
    • FAT32 for smaller cards and broad compatibility
    • exFAT for larger SD cards and large files
  6. Uncheck Quick Format if you want a deeper format.
  7. Click Start.

After formatting, test the SD card by copying files to it and reading them back.

Format a Corrupted SD Card on Mac

  1. Insert the SD card into your Mac.
  2. ディスクユーティリティを開く。.
  3. Select the SD card.
  4. Click Erase.
  5. Choose a format:
    • MS-DOS (FAT) for FAT32
    • exFAT for larger cards
  6. Click Erase.

When the process is complete, eject and reconnect the card.

Format a Corrupted SD Card in a Camera

If the SD card is mainly used in a camera, it is often better to format it in the camera after recovering data.

  1. Insert the SD card into the camera.
  2. Open the camera menu.
  3. Find Format Card or Format Memory Card.
  4. Confirm the operation.
  5. Take a few test photos.
  6. Transfer them to your computer to check whether the card works.

Formatting in the camera can help the card use the file system structure preferred by that camera.

Which File System Should You Choose: FAT32 or exFAT?

The right file system depends on the SD card capacity and the device you use.

ファイルシステム

最適

備考

FAT32

Smaller SD cards, older devices

Good compatibility, but limited for large files

エクストラファット

Larger SD cards, cameras, 4K video

Better for large files and modern devices

エヌティーエフエス

Windows drives

Usually not ideal for cameras or mobile devices

For most modern SDXC and microSDXC cards, exFAT is commonly used. For older devices, FAT32 may be more compatible.

What If the SD Card Is Physically Damaged?

If the SD card has physical damage, software repair may not help. Stop using the card if you notice:

  • Cracks
  • Bent card body
  • Burn marks
  • Water damage
  • Broken contacts
  • Severe overheating
  • Card not detected by any device
  • Device freezes whenever the card is inserted

You can gently clean the metal contacts with a dry, lint-free cloth. However, do not scrape, bend, heat, or disassemble the SD card. If the data is valuable, contact a professional data recovery service. DIY repair attempts may make physical damage worse.

まとめ

A corrupted SD card does not always mean your files are gone forever. In many cases, the data is still recoverable, especially if you stop using the card immediately and avoid formatting it too soon. The safest workflow is: Stop using the corrupted SD card — Recover important files — Try fixing or formatting the SD card only after your data is safe.

必要な場合 recover files from a corrupted SD card, Magic Data Recovery can help scan the card and restore lost photos, videos, documents, and other files before you repair or format it.

Magic Data Recoveryをダウンロード

Windows 7/8/10/11およびWindows Serverをサポート

よくある質問

How do I fix a corrupted SD card without formatting?

You can try another card reader, assign a new drive letter, use Windows Error Checking, run CHKDSK, reinstall drivers, remove write protection, show hidden files, or use Mac Disk Utility First Aid. If the card contains important files, recover data before attempting repair.

How do I recover files from a corrupted SD card?

Connect the SD card to a Windows computer and scan it with data recovery software such as Magic Data Recovery. Preview and select the files you need, then save them to another drive instead of the corrupted SD card.

Why does my SD card say it needs to be formatted?

This usually means the file system is damaged, unsupported, or unreadable. The data may still be recoverable, so do not format the card before recovering important files.

Can CHKDSK fix a corrupted SD card?

CHKDSK can fix some file system errors on a corrupted SD card. Use the command chkdsk E: /f, replacing E: with your SD card drive letter. Recover important files first because CHKDSK may modify the file system.

Will CHKDSK delete files from my SD card?

CHKDSK is designed to repair file system errors, but it may change file records or move damaged file fragments. If your files are important, recover them before running CHKDSK.

How do I fix a corrupted microSD card?

A corrupted microSD card can be repaired using the same methods as a standard SD card. Try another adapter or card reader, recover data, run CHKDSK, assign a drive letter, reinstall drivers, or format the card after recovery.

Why are my SD card files missing but storage still used?

The files may be hidden, the file system may be damaged, or malware may have changed file attributes. Try showing hidden files or scanning the SD card with recovery software.

Can I reuse a corrupted SD card after fixing it?

You can reuse it if it works normally after repair or formatting. However, if the card becomes corrupted repeatedly, shows bad sectors, disconnects often, or fails during file transfer, replace it.

When should I stop trying to fix the SD card myself?

Stop DIY repair if the card is physically damaged, not detected by any device, overheats, freezes your computer, or contains extremely valuable data. In these cases, professional recovery may be safer.

エリン・スミスは、Amagicsoftで最もプロフェッショナルなライターの一人として認められています。過去10年にわたりライティングスキルを磨き続け、何百万人もの読者の技術的な問題解決に貢献してきました。.