Remove-Item Vs [System.IO.File]::Delete() - powershell

Question

I have the following code in an Azure Runbook:
$pathToDownloadedBlob = 'C:\depId-20150904032522\SevenZipSharp.dll'
if ((Test-Path $pathToDownloadedBlob) -eq $true)
{
try
{
Remove-Item -Path $pathToDownloadedBlob
}
catch
{
write-error "Could not delete $pathToDownloadedBlob. - $($error[0])"
exit
}
}
When I use Remove-Item I get this error:
4/7/2015 2:14:14 PM, Error: Remove-Item : The converted JSON string is in bad format.
At DavidTest:45 char:45
+
+ CategoryInfo : InvalidOperation: (System.Unauthor... Boolean force):ErrorRecord) [Remove-Item],
InvalidOperationException
+ FullyQualifiedErrorId : JsonStringInBadFormat,Microsoft.PowerShell.Commands.RemoveItemCommand
When I use [System.IO.File]::Delete($using:path) instead, I get this error:
4/7/2015 2:22:48 PM, Error: Exception calling "Delete" with "1" argument(s): "Access to the path 'C:\Deployment\SevenZipSharp.dll' is denied."
At DavidTest:46 char:46
+
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : UnauthorizedAccessException
I know I don't have permission to delete the file.
However, why is it complaining about a JSON string when I use Remove-Item?
EDIT:
Note this only happens in Azure Automation. However I wasn't truly able to replicate this in Powershell ISE locally because I have permission to files I wish to delete.
UPDATE:I just realised this is only happening for .dll files. If I try to delete a .7z file it works fine.

Answer 1

I would imagine that this is due to the serialization / deserialization of the object being passed between the PowerShell Workflow context, and the InlineScript Workflow Activity, which runs in a separate process by default.
Are you always passing in a [System.String], or are you sometimes passing in a [System.IO.FileInfo] object? If the latter, then you'll probably want to reference the FullName property, rather than passing in the object itself to Remove-Item.
I'm not 100% sure that this is what you're running into, but it's worth discussing.
By the way, as a best practice, always explicitly name your parameters, so other people understand what you're doing. Your call to Remove-Item doesn't include the -Path parameter, by name, because it's positionally at 0. Of course, this isn't a good thing to take for granted when you're asking for help. Better to be verbose.
Hope this helps at least a bit. By the way, is this problem unique to Azure Automation Runbooks, or does it also exist in locally executed PowerShell Workflows?
Edit: This code seems to work just fine for me locally.
workflow test {
$Path = 'C:\dsc\srv01.xml';
InlineScript { Remove-Item -Path $using:Path; };
}
test