If your Windows image is unserviceable, the DISM (Deployment Imaging and Servicing Management) tool can help you fix the issue. DISM is a command-line tool that prepares and repairs Windows images (.wim) or virtual hard disks (.vhd and .vhdx). It can also help you prepare a Windows Preinstallation Environment (Windows PE).
This tool is inbuild on your Windows system, and you can access it easily from the Windows PowerShell or Command Prompt. DISM commands vary based on the edition of Windows you want to server, as well as the state of the image (offline or online).
However, many users have experienced issues when using the DSIM command-line tool to repair or prepare Windows 10 image backup on an external drive. They get the following error message when they attempt to perform the operation:
On this page, you will learn the correct way to run DISM on an external drive to repair Windows 10 image backup.
Run DISM on external drive to repair Windows 10 image backup
If the DISM tool doesn’t work, then you have to clean up the Windows system components.
Press the Windows key and search for cmd. Right-click on Command Prompt and run it as an Administrator. In the Command Prompt window, type the following command and hit ENTER:
Dism.exe /Online /Cleanup-Image /RestoreHealth /Source:C:\RepairSource\Windows
NOTE: In the command above, substitute the
C:\RepairSource\Windows part with the actual location of the repair source.
If you are looking to repair an offline image with the use of a mounted image, you can use:
Dism /Image:C:\offline /Cleanup-Image /RestoreHealth /Source:C:\test\mount\windows
These simple commands will resolve the issue and successfully let you use DISM on external drives.
TIP: You can also fix corrupted Windows Update system files using DISM Tool.