How can I utilize the Add-WindowsCapability function through a proxy in PowerShell?

I am trying to install OpenSSH on a Windows Server 2019 machine in an environment without external network access and with a configured proxy at "". I am using PowerShell with administrative privileges and have set the HTTP_PROXY and HTTPS_PROXY environment variables as follows:

$Proxy = "" $ENV:HTTP_PROXY=$proxy $ENV:HTTPS_PROXY=$proxy 

However, when I try to install OpenSSH using the following command:

Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0 

I receive the following error:

Add-WindowsCapability : Add-WindowsCapability failed. Error code = 0x800f0954 At line:1 char:1 + Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0 + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : NotSpecified: (:) [Add-WindowsCapability], COMException + FullyQualifiedErrorId : Microsoft.Dism.Commands.AddWindowsCapabilityCommand 

Other Invoke-WebRequests I am making seem to have proxy access, but the Add-WindowsCapability command is not working. I am unable to resolve this issue.

2 Answers

The message has error code 0x800f0954, you may want try doing the following steps:

• Open gpedit.msc
• Navigate to Computer Configuration -> Administrative Templates -> System
• Double click on Specify settings for optional component installation and component repair to open its settings
• Check "Enabled" in the popup dialog
• Check Download repair content and optional features directly from Windows Updates instead of Windows Server Updates Services (WSUS)
• Open Powershell, Run gpupdate /force
• Rerun the Add-WindowsCapability again, it should be fixed

I want to share my solution. I searched a lot to solve this issue, because I wanted to solve this without changing the Group Policy's and wanted to use the CAB file as Source.

I used the following command:

Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0 -Source {path to the cab file} -LimitAccess 

Every time I got an error. But then I looked at the logfile: C:\Windows\Logs\CBS\cbs.log and realized that I used the wrong version of the CAB file. In the log file you can also see the expected version. After downloading the right version, everything worked as expected!