Unblocking PowerGUI Add-Ons and PowerShell Modules

When trying to use a Script Editor add-on or a PowerShell module or script you downloaded from the internet, you might every now and then get an error message like this:

Import-Module : File C:\Users\dsotnikov\Documents\WindowsPowerShell\Modules\Add-on.HelpBrowser\Add-on.HelpBrowser.psm1 cannot be loaded. The file C:\Users\dsotnikov\Documents\WindowsPowerShell\Modules\Add-on.HelpBrowser\Add-on.HelpBrowser.psm1 is not digitally signed. The script will not execute on the system. Please see “get-help about_signing” for more details..At line:1 char:184+ @(‘C:\Users\dsotnikov\Documents\WindowsPowerShell\Modules\Add-on.HelpBrowser\Add-on.HelpBrowser.psd1’) | Where-Object { @(Get-Module | %{$_.Path} ) -notcontains $_ } | %{ Import-Module <<<<  $_ }    + CategoryInfo          : NotSpecified: (:) [Import-Module], PSSecurityExc    eption    + FullyQualifiedErrorId : RuntimeException,Microsoft.PowerShell.Commands.ImportModuleCommand

This happens when the downloaded file comes from the internet, is not signed and thus conflicts with your PowerShell execution policy (e.g. RemoteSigned).

If you do trust this particular add-on/module/script to not be malicious (comes from a trusted source, has been inspected and so on), the workaround is quite easy – simply right-click the file (or the entire zip file if the files were zipped) and click Unblock in the Properties dialog box:

(You can also unblock files from PowerShell command-line – and in bulk! – by using Remove-DownloadFlag from PoshCode module.)

Hope this helps!

Dmitry