Reflection Assembly Errors in Powershell - powershell

Question

I have some Powershell code that takes the Apps running on an IIS server and finds the versions of .NET they are running.
$Apps = Get-WebApplication
foreach($App in $Apps) {
$binLocation = "$($App.physicalPath)\bin"
# get all dlls in bin folder
$dllFolder = Get-Item -Path $binLocation
$dlls = $dllFolder.GetFiles("*.dll")
# analyze dll .net version
$set = New-Object System.Collections.Generic.HashSet[String]
$dlls | ForEach-Object {
$set.Add([Reflection.Assembly]::ReflectionOnlyLoadFrom("$binLocation\$($_.Name)").ImageRuntimeVersion) | Out-Null
}
# print all dll .NET version
$App
$set
}
However when I run this on my server I get 2 types of error;
Exception calling "ReflectionOnlyLoadFrom" with "1" argument(s): "API restriction: The
assembly 'file:///D:\inetpub\wwwroot\OABS_ECRM\bin\WebGrease.dll' has already loaded from a
different location. It cannot be loaded from a new location within the same appdomain."
At line:13 char:74
+ $set.Add([Reflection.Assembly]::ReflectionOnlyLoadFrom ("$binLocation\$($_.Name ...
+ ~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : FileLoadException
and,
Exception calling "ReflectionOnlyLoadFrom" with "1" argument(s): "Could not load file or
assembly 'file:///D:\inetpub\wwwroot\Tablet\bin\epengine.dll' or one of its dependencies.
The module was expected to contain an assembly manifest."
At line:13 char:74
+ $set.Add([Reflection.Assembly]::ReflectionOnlyLoadFrom("$binLocation\$($_.Name ...
+ ~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : BadImageFormatException
I seem to get the .NET versions running on each app from the script but I was wondering what caused these errors and if they can be cleared. I need to solve this in powershell.

Answer 1

Loading multiple DLLs with the same identity into the same AppDomain will give you the first exception.
See my workaround at https://stackoverflow.com/a/62379741/920618.