When installing RSAT tools onto Windows it fails with the error code 0x800f0954.

PS C:\> Get-WindowsCapability -Name RSAT.ActiveDirectory* -Online | Add-WindowsCapability -Online
Add-WindowsCapability : Add-WindowsCapability failed. Error code = 0x800f0954
At line:1 char:61
+ ... y -Name RSAT.ActiveDirectory* -Online | Add-WindowsCapability -Online
+                                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Add-WindowsCapability], COMException
    + FullyQualifiedErrorId : Microsoft.Dism.Commands.AddWindowsCapabilityCommand

To fix:

1. Run "gpedit.msc" as Administrator to edit your local computer policy.
2. Navigate to "Computer Configuration\Administrative Templates\System"
3. Locate setting "Specify settings for optional component installation and component repair"
4. Set to Enabled and check the box “Download repair content and optional features directly from Windows Updates instead of Windows Server Updates Services (WSUS)“.
5. Click Apply and OK.

Now try the install again and it should work as below:

PS C:\temp> Get-WindowsCapability -Name RSAT.ActiveDirectory* -Online | Add-WindowsCapability -Online


Path          :
Online        : True
RestartNeeded : False