How to fix "The WinRM client cannot process the request. The resource URI is not valid: it does not contain keys, but the class selected is not a singleton."

In the WS-Management protocol, a singleton class is a class that only ever has one instance (for example, the operating system configuration or local time). For singleton classes, the Resource URI is enough to locate the resource. However, for standard classes that can have multiple instances (like local users, network adapters, or services), you must provide specific keys (like a name or ID) so WinRM knows exactly which instance you want to manage. If you target a multi-instance class using a basic URI without these keys, WinRM rejects the request with this specific error.

Step-by-Step Fixes

Depending on how you are executing the command, use one of the following methods to resolve the issue:

Method 1: Provide the Required Keys in the Command

If you are using Get-WSManInstance or similar WSMan cmdlets, you must pass the specific instance keys using the -SelectorSet parameter.

1. Open PowerShell as an Administrator.
2. Modify your command to include the exact key of the instance you want to query.
   • Incorrect (Causes Error):

     Get-WSManInstance -ResourceURI "wmicimv2/Win32 Service" -ComputerName "RemotePC"

   • Correct (Fixed with SelectorSet):

     Get-WSManInstance -ResourceURI "wmicimv2/Win32 Service" -SelectorSet @{Name="wuauserv"} -ComputerName "RemotePC"

     (Note: Replace "wuauserv" with the specific service name or instance key you need to target).

Method 2: Switch to CIM or WMI Cmdlets (Recommended)

If your goal is simply to query or manage remote Windows Management Instrumentation (WMI) classes, using CIM cmdlets is much easier because they handle instance formatting automatically over WinRM.

1. Open PowerShell.
2. Instead of using the raw WS-Management cmdlets, use Get-CimInstance.
   • Fixed Command:

     Get-CimInstance -ClassName Win32 Service -ComputerName "RemotePC"

3. If you want to filter for a specific instance without manual URI building, add a filter argument:
   • Fixed Command with Filter:

     Get-CimInstance -ClassName Win32 Service -Filter "Name = 'wuauserv'" -ComputerName "RemotePC"

Method 3: Fix WinRM Connection Endpoint Configuration

If this error appears while using a third-party management software or an automated script, the software might be hitting the wrong default configuration endpoint.

1. Open PowerShell as an Administrator.
2. Check your current WinRM listener configuration by running:

   winrm e winrm/config/listener

3. Reset the WinRM configuration to its default secure settings to clear out invalid custom routing URIs:

   winrm quickconfig -q

4. Restart the WinRM service to apply changes:

   Restart-Service WinRM