Cannot load dll assembly in windows 10 (Exception from HRESULT: 0x80131515) - powershell

Question

I was trying to load the compiled dll assembly of JSON.NET. However I get the following error message:
PS C:\Users\tamas\Desktop\garbage> Add-Type -path .\Newtonsoft.Json.dll
Add-Type : Could not load file or assembly 'file:///C:\Users\tamas\Desktop\garbage\Newtonsoft.Json.dll' or one of its d
ependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)
At line:1 char:1
+ Add-Type -path .\Newtonsoft.Json.dll
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [Add-Type], FileLoadException
+ FullyQualifiedErrorId : System.IO.FileLoadException,Microsoft.PowerShell.Commands.AddTypeCommand
On a different computer, under windows 7 I was able to do the same thing without any problem.
What could be the cause and the solution?
My .NET version:
PS C:\Users\tamas\Desktop\garbage> [System.Environment]::Version
Major Minor Build Revision
----- ----- ----- --------
4 0 30319 42000
PowerShell version:
PS C:\Users\tamas\Desktop\garbage> $Host.Version
Major Minor Build Revision
----- ----- ----- --------
5 1 14393 206

Answer 1

Thanks to #martin-brandl 's suggeston I was able to figure out the problem (I actually had to modify his code, becuase it did not output anything ($global:error[0].Exception has no LoaderExceptions field.))
PS C:\Users\tamas\Desktop\garbage>
>> try
>> {
>> Add-Type -Path .\Newtonsoft.Json.dll
>> }
>> catch
>> {
>> write-host $global:error[0].Exception.InnerException
>> }
System.NotSupportedException: An attempt was made to load an assembly from a network location which would have caused th
e assembly to be sandboxed in previous versions of the .NET Framework. This release of the .NET Framework does not enabl
e CAS policy by default, so this load may be dangerous. If this load is not intended to sandbox the assembly, please ena
ble the loadFromRemoteSources switch. See http://go.microsoft.com/fwlink/?LinkId=155569 for more information.
It turned out that since the dll file was from an external source, for safety reasons powershell threw an exception. Using th UnsafeLoadFrom(...) method I was able to load the dll assembly:
PS C:\Users\tamas\Desktop\garbage> [System.Reflection.Assembly]::UnsafeLoadFrom("c:\users\tamas\Desktop\garbage\Newtonso
ft.Json.dll") # absolute path required here!!
GAC Version Location
--- ------- --------
False v4.0.30319 C:\Users\tamas\Desktop\garbage\Newtonsoft.Json.dll
More info on this issue can be found on the msdn site here .

Answer 2

I can't tell you which of the dependencies you are missing but I can tell you how to find it out. Just surround your Add-Type within a try-catch cand retrieve the LoaderException:
try
{
Add-Type -Path .\Newtonsoft.Json.dll
}
catch
{
$global:error[0].Exception.LoaderExceptions | % { Write-Host $_ }
}