Cmdlets that deal with PSSessions created on ContainerId throw a NullReferenceException when creating the session. This is true for New-PSSession, Enter-PSSession and Invoke-Command, among maybe others.

The stack trace is this:

Object reference not set to an instance of an object.
   at System.Management.Automation.Runspaces.ContainerProcess.GetContainerProperties()
   at Microsoft.PowerShell.Commands.PSExecutionCmdlet.CreateHelpersForSpecifiedContainerSession()

For me the line that fails is inside GetContainerPropertiesInternal of the class System.Management.Automation.Runspaces.ContainerProcess in System.Management.Automation.dll.

ContainerObRoot = (string) computeSystemPropertiesType.GetProperty("ObRoot").GetValue(obj);

Steps to reproduce

To reproduce this a running container is required.

New-PSSession -ContainerId <TheContainerId> -RunAsAdministrator

Expected behavior

An instance of PSSession should be created.

Actual behavior

A NullReferenceException is thrown.

Environment data

Name                           Value
----                           -----
PSVersion                      7.0.3
PSEdition                      Core
GitCommitId                    7.0.3
OS                             Microsoft Windows 10.0.18363
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0