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Troubleshooting#

Application appears frozen / stuck at a percentage#

Expected behaviour. DISM driver injection operations run silently in the background and take 10–15 minutes each. The UI does not update during these periods.

  • Do not close the application
  • Watch the Operation Log — it updates between major steps
  • Total expected time is 45–90 minutes for a full run with multiple editions
  • If you selected all editions (typically 5–10), multiply per-edition time accordingly

"Access Denied" or administrator errors#

Cause: The application is not running with elevated privileges.

Fix: Right-click the executable or script and select Run as administrator. The application will also prompt automatically to restart with elevation.

To verify you are running as admin in PowerShell:

([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)

This should return True.

"Execution Policy" error (PowerShell script only)#

Cause: Windows is blocking script execution.

Fix: Bypass the execution policy for the current session only:

Set-ExecutionPolicy -Scope Process -ExecutionPolicy Bypass
.\WinImagePrep_V3.ps1

This does not change the system-wide policy.

"Error 0x800F0823" — Access denied during DISM#

Cause: A WIM image is already mounted from a previous run or failed operation.

Fix: Click Repair/Cleanup in the application. This force-dismounts all mounted images and clears the working directories.

Alternatively, run manually in an elevated PowerShell prompt:

# List mounted images
Get-WindowsImage -Mounted

# Force unmount all
Get-WindowsImage -Mounted | ForEach-Object {
    Dismount-WindowsImage -Path $_.Path -Discard
}

# Clean working directories
Remove-Item -Path C:\Win11ImagePrep\Temp\Mount\* -Recurse -Force
Remove-Item -Path C:\Win11ImagePrep\Temp\ExtractedISO\* -Recurse -Force
Remove-Item -Path C:\Win11ImagePrep\Temp\Drivers\* -Recurse -Force

"Not enough disk space"#

Cause: Less than 25GB is available on C:.

Fix: Free up space before retrying:

  • Delete C:\Windows\Temp\ contents
  • Run Disk Cleanup → Clean up system files to remove Windows Update files
  • Check C:\Win11ImagePrep\Temp\ for leftover working files from previous runs and delete them

"No USB drives found"#

Cause: The USB drive is not being detected.

Fix:

  • Ensure the USB drive is physically connected
  • Try a different USB port
  • Click the Refresh button in the application
  • Open Disk Management (diskmgmt.msc) to confirm the drive appears in Windows
  • Try a different USB drive

USB shows "Not formatted" after creation completes#

Cause: Windows sometimes shows this briefly while the FAT32 volume is being registered.

Fix:

  • Safely eject and reinsert the USB
  • If prompted to format, click Cancel — do not reformat
  • Verify files exist on the drive in File Explorer before assuming it failed
  • Test by booting a device from the USB in UEFI mode

"The file install.wim was not found"#

Cause: Some Windows ISOs use install.esd instead of install.wim. The tool requires install.wim.

Fix: Convert the ESD to WIM first using DISM in an elevated PowerShell prompt:

# Check available edition indexes
dism /Get-WimInfo /WimFile:install.esd

# Export each edition to install.wim (repeat for each index needed)
dism /Export-Image /SourceImageFile:install.esd /SourceIndex:1 /DestinationImageFile:install.wim /Compress:max /CheckIntegrity

Run the export command for each edition index, then use the resulting install.wim alongside the other ISO files.

Antivirus blocking the script or application#

Cause: Security software flagging PowerShell scripts or executables that use DISM, disk partitioning, or WPF controls.

Fix: This is a false positive. Options:

  • Add an exclusion for the file in your antivirus settings
  • Use the Windows Application instead of the script (compiled binaries are less commonly flagged)
  • Review the open source code to verify the tool before adding an exclusion

Operation fails mid-way / application crashes#

If the application crashes or is forcibly closed during an operation, WIM images may be left in a mounted state. On the next launch, use Repair/Cleanup to recover.

For manual cleanup:

# Unmount all stuck WIM images
Get-WindowsImage -Mounted | ForEach-Object {
    Dismount-WindowsImage -Path $_.Path -Discard
}

# Dismount any ISO images
Get-DiskImage | Where-Object Attached | ForEach-Object {
    Dismount-DiskImage -ImagePath $_.ImagePath
}

# Clean working directories
Remove-Item -Path C:\WinImagePrep\Windows11\* -Recurse -Force -ErrorAction SilentlyContinue
Remove-Item -Path C:\WinImagePrep\Drivers\* -Recurse -Force -ErrorAction SilentlyContinue
Remove-Item -Path C:\WinImagePrep\Mount\* -Recurse -Force -ErrorAction SilentlyContinue

Performance — operations are very slow#

  • Use an SSD for C:\WinImagePrep\ — the working directory is heavily I/O intensive during WIM mounting and driver injection
  • Disable real-time antivirus scanning during the operation — scanning every file written by DISM significantly increases time
  • Select fewer editions — each edition adds 10–15 minutes; choose only the editions you plan to deploy
  • Close other applications to free RAM for DISM operations

Reporting Bugs#

Open an issue on the GitHub repository and include:

  • Windows version and build number
  • Tool version (Windows Application version or script file name)
  • Full contents of the Operation Log from the session
  • The exact error message received