Enable Silverlight Plugin (NPAPI) in Chrome using registry key fix - google-chrome

Question

I have created a Powershell script to add the npapi and Silverlight* registry keys to enable Silverlight in Google Chrome. The Powershell script works fine and adds the two registry keys, however the Silverlight plugin is still disabled in Chrome and when I load any Silverlight based sites I get the “Install Silverlight” popup. I have restarted the machine and still the Silverlight plugin is disabled.
However, if I go into the registry and delete just the npapi and Silverlight* registry keys and re-create them (String value - REG_SZ), when I reload the page in Chrome, Silverlight is now enabled and the site loads perfectly. I don’t understand what’s going on.
The powershell script creates these keys but only when I delete them and re-create them manually do they take effect and the Silverlight plugin is enabled. Then if I go into chrome://plugins, Chrome reports that the Silverlight plugin is “Enabled by Enterprise policy”. I have also run the script on another machine and the exact same thing happens. Has anyone else experienced this and does anyone know the fix or what I am doing wrong?
Powershell Script used to create the npapi and Silverlight* registry keys:
function Create-Path {
[CmdletBinding()]
param (
[Parameter(ValueFromPipeline = $false, Mandatory = $true)]
[string]$Path
,
[Parameter(ValueFromPipeline = $true, Mandatory = $false)]
[switch]$OverwriteIfExists
)
process {
If(($OverwriteIfExists.IsPresent) -or (-not (Test-Path $Path))) {
New-Item $Path -Force | out-null
}
}
}
function Get-RegistryKeyWithValue {
[CmdletBinding()]
param (
[Parameter(ValueFromPipeline = $false, Mandatory = $true)]
[string]$Path
,
[Parameter(ValueFromPipeline = $true, Mandatory = $true)]
[string]$Value
)
process {
$properties = Get-Item $Path | select -ExpandProperty Property
$properties | %{
$property = Get-ItemProperty -Path $Path -Name $_
if ($property.$_ -eq $Value) {
write-output $property
}
}
}
}
function Get-NextKeyInPath {
[CmdletBinding()]
param (
[Parameter(ValueFromPipeline = $false, Mandatory = $true)]
[string]$Path
)
process {
try {
write-output ((Get-Item $Path -ErrorAction Stop | select -ExpandProperty Property | Measure-Object -Maximum).Maximum + 1) | out-string
} catch {
write-output "1"
}
}
}
function Create-ChromeEnabledPluginPolicy {
[CmdletBinding()]
param (
[Parameter(ValueFromPipeline = $true, Mandatory = $true)]
[string]$Value
)
begin {
$ChromePluginPolicyPath = "HKLM:\SOFTWARE\Policies\Google\Chrome\EnabledPlugins"
Create-Path $ChromePluginPolicyPath
}
process {
if (-not (Get-RegistryKeyWithValue -Path $ChromePluginPolicyPath -Value $Value)) {
$keyName = Get-NextKeyInPath -Path $ChromePluginPolicyPath
New-ItemProperty -path $ChromePluginPolicyPath -Name $keyName -Value $Value -PropertyType String
}
}
}
"npapi", "Silverlight*" | Create-ChromeEnabledPluginPolicy

Answer 1

The code:
process {
try {
write-output ((Get-Item $Path -ErrorAction Stop | select -ExpandProperty Property | Measure-Object -Maximum).Maximum + 1) | out-string
} catch {
write-output "1"
}
}
Seems to return something more than a single string.
Amending to the following resolves the issue:
process {
try {
[int]$i = ((Get-Item $Path -ErrorAction Stop | select -ExpandProperty Property | Measure-Object -Maximum).Maximum + 1)
write-output ([string]$i)
} catch {
write-output "1"
}
}
A simplified demo of the issue & solution:
Run the following code: New-ItemProperty -Path 'HKLM:\SOFTWARE\JohnLBevan' -Name (1 | out-string) -PropertyType String -Value 'test'
Now open regedit and create a key with name 1; it succeeds (i.e. you have two keys called 1; so clearly some control/non displayable character is being added in our PS script).
If you try to add a third key called 1 using either method (regedit or powershell) you'll get an error due to a key with that name already existing (showing that there is a unique check in place; it's just our original 1s aren't unique)
If you try either of the following code snippets, things work as expected:
New-ItemProperty -Path'HKLM:\SOFTWARE\JohnLBevan' -Name "1" -PropertyType String -Value 'test'
New-ItemProperty -Path'HKLM:\SOFTWARE\JohnLBevan' -Name [string]1 -PropertyType String -Value 'test'
(Disclosure: I work with #jwoods83, so had the advantage of seeing the issue / playing with it directly)