Dism Error 87 Fixed ^new^ -

How to Fix DISM Error 87: The "Option is Unknown" Problem

If you’ve ever tried to repair a Windows system image using the Deployment Imaging and Service Management (DISM) tool, you might have been greeted by a frustrating message:

"Error: 87 – The option is unknown."

This error stops your repair process in its tracks. The good news is that it’s almost always caused by a simple typo or syntax mistake. Here’s everything you need to know to fix DISM Error 87 quickly and safely.

Full repair sequence

  1. Run SFC:

    sfc /scannow

    If SFC repairs files, reboot and re-run DISM.

  2. DISM Check and Restore (standard approach for Windows 8/10/11):

    dism /online /cleanup-image /checkhealth
dism /online /cleanup-image /scanhealth
dism /online /cleanup-image /restorehealth

    If /restorehealth fails with Error 87, supply a source as above. dism error 87 fixed

  3. Use a Windows ISO as source (preferred):

    • Mount ISO, note drive letter (e.g., D:), then: 
      dism /online /cleanup-image /restorehealth /source:WIM:D:\sources\install.wim:1 /limitaccess
    • If ISO has install.esd, convert or point to install.esd: 
      dism /online /cleanup-image /restorehealth /source:ESD:D:\sources\install.esd:1 /limitaccess
    • If index unknown, list indexes: 
      dism /get-wiminfo /wimfile:D:\sources\install.wim

  4. If DISM binary mismatch suspected:

    • Ensure running system32\dism.exe on 64-bit systems. Run: 
      %windir%\system32\dism.exe /?
    • If using Windows ADK or custom WinPE, use matching DISM for the OS.

  5. Reset Windows Update components (if DISM uses online sources): How to Fix DISM Error 87: The "Option

    • Stop services: wuauserv, cryptSvc, bits, msiserver
    • Rename SoftwareDistribution and Catroot2 folders
    • Restart services (Commands provided on request.)

  6. Repair via in-place upgrade (if image servicing keeps failing):

    • Mount ISO and run setup.exe, choose "Keep personal files and apps".

  7. Reinstall/repair Windows ADK or remove third-party tools if they replaced DISM.

  8. For offline images, ensure using correct switches: Run SFC: sfc /scannow

    dism /image:C:\mountdir /cleanup-image /restorehealth /source:wim:X:\sources\install.wim:1

To scan health:

DISM /Online /Cleanup-Image /ScanHealth

✅ Note: There is no space after slashes (/), and RestoreHealth is one word.

3. Reproduction (example commands that trigger Error 87)

  • Typo or wrong spacing:
    • dism /online /cleanup-image /restorehealth (missing colon or correct spacing? this example is actually valid; error arises with incorrect capitalization or stray characters)
  • Using /Image when you meant /Online:
    • dism /image:C:\mount /cleanup-image /restorehealth (RestoreHealth is only supported for /Online or with a source)
  • Using unsupported options for OS:
    • dism /online /enable-feature /featurename:NetFx3 /All /LimitAccess /Source (missing proper source path)

Note: Reproducing requires specific misuses; in practice Error 87 is flagged before long operations complete.