Unable to install optional features in Windows 10

We use an on-prem WSUS server and we were no longer able to install optional features. This is a quick, temporary, workaround so you can get them installed.

The underlying issue is that Windows tries to pull the optional features from Windows Update. If those are not being downloaded to your on-prem WSUS server it cannot install them. The other issue is that there is no log messages anywhere that states it couldn't find it. Just that the install starts and a few seconds later, stops.

The solution I found is to temporarily disable the WSUS configuration on the client.

To do this, open up regedit and navigate to Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU

Change UseWUServer to a 0 and, if it is running, restart the Windows Update service.

After you have installed your tools, like OpenSSH Client, change that value back to a 1 and restart the Windows Update service.