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How to Use Win32 Disk Imager (Step-by-Step)

Everything you need after download: first run, writing an image to USB/SD, verifying, making a backup, restoring full card size, and validating checksums—plus speed and safety tips.

1) Prepare your PC & media

What you need

  • A .img or compatible .iso file.
  • A USB flash drive or SD/microSD card large enough for the image.
  • A reliable USB 3.x port and good quality card reader (UHS-I recommended).

Best practices

  • Back up important data—writing will erase the target.
  • Close apps that might lock files: ISO mounters, zip tools, antivirus scans.
  • Prefer a short, direct cable; avoid front-panel hubs.
Tip: Put images in a simple folder like C:\Images\ (short paths, fewer permission issues).

2) Launch & basic layout

Win32 Disk Imager is portable—just extract and run. For raw device access, right-click the app and select Run as administrator.

Main controls

  • Image File: Pick your .img/.iso.
  • Device: Choose the target USB/SD drive letter.
  • Write / Read: Write the file to the device, or read the device back to a file.
  • Hash / Verify: Calculate SHA-256/SHA-1/MD5; verify device vs. file.

Safety & visibility

  • Double-check the Device before writing.
  • Keep the log panel visible—errors and progress appear there.

3) Write an image to USB/SD

  1. Insert the target USB/SD card and wait for Windows to detect it.
  2. Open Win32 Disk Imager as Administrator.
  3. Click Image File and select your .img/.iso.
  4. In Device, choose the correct drive letter (match size/label).
  5. Click Write, confirm the warning, and wait for completion.
Warning: Writing overwrites the device completely. Make sure you selected the right drive.
Heads-up: After writing Linux-based images, Windows may prompt to format the drive. Click Cancel; it’s expected.

4) Verify the write (recommended)

Verification re-reads the device and compares every byte with the source image—catching cable/media issues before first boot.

  1. Leave the device inserted after writing.
  2. Click Verify Image (or run Hash on both file and device and compare).
  3. If differences are found, try a different reader/port/cable, or a new device.

5) Read & backup a device to an image

Use Read to clone your SD/USB to a file—perfect before risky changes or for quick disaster recovery.

  1. Insert the source device.
  2. Choose a destination path and filename in Image File (e.g., C:\Images\MyBackup.img).
  3. Select the correct Device.
  4. Click Read and wait for completion.
Save space: Compress the image afterward with 7-Zip (.7z/.xz) or shrink first using a tool like PiShrink (Linux/macOS) before compressing.

6) Restore your SD/USB to full size (after imaging)

Imaging can leave Linux partitions Windows can’t resize. Use DiskPart to reset the device.

# Open Command Prompt (Admin) and run:
diskpart
list disk
select disk <N>      # choose carefully by size
clean                 # wipes partition table
create partition primary
format fs=fat32 quick
assign
exit
Careful: Triple-check the disk number so you don’t wipe the wrong drive.

7) Verify file integrity (SHA-256)

Compare the image’s hash with the value on the download page, or generate device and file hashes inside the app.

PowerShell (Windows)

Get-FileHash \"C:\Images\yourfile.img\" -Algorithm SHA256

Inside Win32 Disk Imager

  • Click Hash → choose SHA-256.
  • Generate for the image file and (optional) for the device after writing.
  • Compare the results—they must match to be identical.

8) Improve write speed & reliability

  • Use a USB 3.x port on the motherboard; avoid hubs.
  • Choose quality media (A2/UHS-I SD cards; brand-name USB drives).
  • Temporarily pause antivirus scanning for your image folder.
  • For sustained throughput: Device Manager → your removable drive → Policies → Better performance (then always “Safely remove”).

FAQ & safety notes

Windows asks to format after writing—should I?
Click Cancel. The image likely uses Linux partitions Windows can’t read—that’s normal.
“Access denied (Error 5)”—what do I do?
Run the app as Administrator. Close apps that lock the device or image (Explorer, ISO mounters, AV). If needed, clear read-only with: 
diskpart
list disk
select disk <N>
attributes disk clear readonly
exit
Image doesn’t fit “same size” card.
Two cards labeled the same capacity can differ slightly. Use an equal-or-bigger device, or shrink the source (e.g., PiShrink) before creating the image.
Verify fails—now what?
Try a different reader/port/cable; re-download the image and compare SHA-256; suspect failing/counterfeit media if failures persist.

9) Special ISO notes (UEFI/BIOS expectations)

Many .iso files can be written like raw images. Some vendor ISOs, however, expect a specific installer or media creation process.

  • If your ISO vendor provides a media creation tool, prefer that method.
  • When raw-write succeeds but target won’t boot, check the image’s UEFI vs BIOS support and your device’s boot mode.
  • For distributions that discourage raw writes to USB on Windows, use their recommended utility or convert to a raw image as instructed by the vendor.
Tip: If in doubt, test with a small, known-good image (e.g., a tiny rescue image) to rule out reader/USB issues.

10) Shrink a Raspberry Pi image with PiShrink (Linux/macOS or WSL)

Use PiShrink to make an image smaller so it fits on slightly smaller cards and transfers faster. After first boot, most OSes grow the filesystem automatically.

Linux/macOS

wget https://raw.githubusercontent.com/Drewsif/PiShrink/master/pishrink.sh
chmod +x pishrink.sh
sudo ./pishrink.sh source.img shrunken.img   # creates a smaller image

Copy shrunken.img back to Windows and write it with Win32 Disk Imager.

Windows via WSL

  1. Install WSL (Ubuntu) and place your .img in a simple path (e.g., C:\Images\).
  2. From WSL, run the PiShrink commands above (access the Windows path at /mnt/c/Images).
If WSL can’t access the file due to permissions, move it to a non-synced folder (not Desktop/OneDrive) and retry.

11) Handling large images (>4 GB): store on exFAT, write as raw

Windows FAT32 volumes cannot store files larger than 4 GB. Store big images on NTFS or exFAT and write them normally. The target device’s filesystem will be replaced by the image’s partitions during the write.

  • Keep your image library on NTFS/exFAT to avoid copy errors.
  • Do not convert the image itself—Win32 Disk Imager expects a raw file to write.

12) If verification fails — choose your next step

  1. Check the source: Re-download and compare SHA-256 with the site’s value.
  2. Swap hardware: Try another reader/cable/port (prefer motherboard USB 3.x).
  3. Retest media: Try a different SD/USB. Persistent failures often mean bad/counterfeit media.
  4. Shorten the path: Move the image to C:\Images\ and run as Administrator.

13) Make multiple identical USBs/SDs reliably

Workflow (recommended)

  1. Write the image to your first device and run Verify.
  2. Use Read to create a “golden” image (golden.img) from the verified device.
  3. Write golden.img to each subsequent device and verify each one.
This ensures the exact bytes you validated are copied to every unit.

Optional: PowerShell helper to re-hash

$golden = "C:\Images\golden.img"
$dev    = "E:"  # change to your device letter
$hash1  = Get-FileHash $golden -Algorithm SHA256
$hash2  = Get-FileHash "$dev\" -Algorithm SHA256 # if mounted volume exists
$hash1.Hash; $hash2.Hash

If the device has no mounted volume, rely on Win32 Disk Imager’s Verify after write.

14) Accessibility & no-mouse usage tips

  • Use Tab/Shift+Tab to move focus between fields and buttons.
  • When Windows prompts for admin elevation, use arrow keys and Enter.
  • Keep the log visible (screen readers can read the latest status messages).

15) Quick-start (1 page)

  1. Run Win32 Disk Imager as Administrator.
  2. Select the image file and the correct Device.
  3. Click Write → wait → Verify Image.
  4. If Windows asks to format after writing, click Cancel (expected for Linux images).
  5. To reuse the device in Windows, run DiskPart clean + format (see §6).
Keep images in C:\Images\, use a short cable, and prefer a motherboard USB 3.x port.