Notice the before each forward slash ( / ). Re-type the command carefully ensuring these spaces are included, then press Enter . 2. Run Command Prompt as Administrator
Boot from a Windows USB, open Repair tools → Command Prompt, then run DISM offline:
You see: Error: 87 – The option is unknown to this version of DISM. dism error 87 fixed
How to Fix DISM Error 87: A Step-by-Step Guide If you’ve tried to repair your Windows image using the Deployment Image Servicing and Management (DISM) tool only to be met with you’re not alone. This is one of the most common DISM errors, and while it looks intimidating, it usually boils down to a simple syntax mistake or a service glitch.
Run a lower-level health check first.
Right-click the Start button and select or PowerShell (Admin) . Run the command again. 2. Restart Your Computer
DISM /Online /Cleanup-Image /RestoreHealths ❌ (extra "s" on RestoreHealth) Notice the before each forward slash ( / )
If you still get error 87, try a simpler DISM command to verify DISM itself works:
Unlike errors related to missing files (Error 0x800f081f) or corrupted stores (Error 0x800f0906), Error 87 is a . DISM is telling you, "I understood that you wanted me to do something, but the instructions (parameters/switches) you gave me do not make sense in this context." Run Command Prompt as Administrator Boot from a
– Create a file called repair.bat with your working command to avoid re-typing.