Hi worldwar2,
I'm Paul and I'm here to help you with your concern.
Please try the solutions below.
- Install the latest Windows Updates.
- Use System File Checker to check and fix corrupted system files that may be the cause of the issue. Please refer to the link.
https://support.microsoft.com/en-us/help/402652...
After that, try to install the optional feature.
- Perform Clean Boot. Refer to this link.
https://support.microsoft.com/en-us/help/929135...
Then while in this state, try to install the optional feature.
I hope this helps. Feel free to ask back any questions and keep me posted.