Was manually updating the Powershell help on a development server (without direct internet access) and received the following:

PS C:\Windows\system32> update-help -SourcePath D:\Software\Microsoft\PowershellHelp

update-help : Failed to update Help for the module(s) 'PSDesiredStateConfiguration' with UI culture(s) {en-US} :
Unable to retrieve the HelpInfo XML file for UI culture en-US. Make sure the HelpInfoUri property in the module
manifest is valid or check your network connection and then try the command again.
At line:1 char:1
+ update-help -SourcePath D:\Software\Microsoft\PowershellHelp
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ResourceUnavailable: (:) [Update-Help], Exception
    + FullyQualifiedErrorId : UnableToRetrieveHelpInfoXml,Microsoft.PowerShell.Commands.UpdateHelpCommand

The Solution:
Run Powershell as Administrator when attempting to update Powershell help files.

Environmental Information:
Powershell Version: 4.0