Issue the following from a new pwsh session:
Add-Type -AssemblyName System.Windows.Forms
$MainForm = New-Object System.Windows.Forms.Form
Test-Connection 'PC-IAN'

Test-Connection should run and produce similar output to the following:


   Destination: PC-IAN

Ping Source           Address                   Latency BufferSize Status
                                                   (ms)        (B)
---- ------           -------                   ------- ---------- ------
   1 PC-IAN           fe80::5158:e71e:c447:7e86       0         32 Success
   2 PC-IAN           fe80::5158:e71e:c447:7e86       0         32 Success
   3 PC-IAN           fe80::5158:e71e:c447:7e86       0         32 Success
   4 PC-IAN           fe80::5158:e71e:c447:7e86       0         32 Success

The pwsh session ‘hangs’ (i.e. doesn’t respond at all after Test-Connection).

Test-Connection produces the expected results if $MainForm = New-Object System.Windows.Forms.Form IS NOT run beforehand.

$MainForm = New-Object System.Windows.Forms.Form is successful and the resulting form can be processed if Test-Connection IS NOT run afterwards.

Name                           Value
----                           -----
PSVersion                      7.0.0-rc.1
PSEdition                      Core
GitCommitId                    7.0.0-rc.1
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