Dism Error 87 Fixed -

Sometimes, DISM fails because the background services it relies on are not running correctly. Restarting these services can clear the parameter error.

How to do it:

Try a basic check first:

DISM /Online /Cleanup-Image /CheckHealth

If that works, the problem is likely in your longer command’s syntax, not DISM itself.

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.

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.

| Mistake | Correction | |---------|-------------| | DISM /Online /Cleanup-Image /Restore Health | Remove space: /RestoreHealth | | DISM /Online /Cleanup-Image /RestoreHealth /Source:... | Use correct syntax with Source after RestoreHealth | | Using DISM /RestoreHealth alone | Must include /Online /Cleanup-Image | | Typo in command | Double-check spelling and slashes |