Dism Error 87 Fixed -

DISM only recognizes forward slashes (/) for options. Backslashes (\) will trigger Error 87 instantly.

Wrong: DISM \Online \Cleanup-Image Right: DISM /Online: /Cleanup-Image

If you are copying commands from a website, paste them into Notepad first and look for auto‑formatted slashes.

DISM (Deployment Imaging Servicing and Management) is a powerful Windows tool for repairing system images. Error 87 usually appears when you mistype a command, use incorrect syntax, or run an unsupported option in your current Windows environment.

In 90% of cases, Error 87 is caused by a missing colon after Online. Many old tutorials omit the colon, but modern Windows versions require it strictly. dism error 87 fixed

Incorrect (causes Error 87):

DISM /Online /Cleanup-Image /RestoreHealth

Correct (works perfectly):

DISM /Online: /Cleanup-Image /RestoreHealth

Notice the colon after Online? That tiny punctuation mark is critical. Apply this to any DISM command:

Pro Tip: Always write Online: with a colon and a space before the next switch. DISM only recognizes forward slashes ( / ) for options

| Error Code | Meaning | Typical Fix | |------------|---------|--------------| | Error 87 | Unknown option or bad syntax | Check spelling, slashes, colons | | Error 0x800f081f | Source files not found | Verify /Source path and index | | Error 0x800f0906 | CBS manifest corruption | Re-run with clean ISO source | | Error 0x80070005 | Access denied | Run as administrator |

Scan health:

Restore health (online, using Windows Update):

Restore using a local source (install.wim or install.esd):

Use exactly these parameter names (case-insensitive) and ensure spaces and slashes are correct.

In rare cases, the error appears even with correct syntax. This usually means the DISM component itself is damaged. Try these steps:

Users most commonly encounter Error 87 when running: Notice the colon after Online

However, the error can also appear when using /Get-Packages, /Add-Driver, or /Apply-Image commands.

Wrong:

DISM /online /cleanup-image /restorehealth /source D:\sources\install.wim /limitaccess

Corrected:

DISM /Online /Cleanup-Image /RestoreHealth /Source:D:\sources\install.wim:1 /LimitAccess