Syntax error with Uninstaller using Powershell - windows

Question

I'm trying to get my universal uninstaller working. Here is my code:
CLS
$Software = "Zoom"
$Filter = "*" + $Software + "*"
$Program = $ProgUninstall = $FileUninstaller = $FileArg = $NULL
try
{
if (Test-Path -Path "HKLM:\SOFTWARE\WOW6432Node")
{
$programs = Get-ItemProperty -Path "HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\*" -ErrorAction Stop
}
$programs += Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*" -ErrorAction Stop
$programs += Get-ItemProperty -Path "Registry::\HKEY_USERS\*\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*" -ErrorAction SilentlyContinue
}
catch
{
Write-Error $_
break
}
foreach($Program in $Programs)
{
$ProgDisplayName = $Program.DisplayName
$ProgUninstall = $Program.UninstallString
if($ProgDisplayName -like $Filter)
{
#$Program
$aux = $ProgUninstall -split #('\.exe'),2,[System.StringSplitOptions]::None
$Uninstaller = (cmd /c echo $($aux[0].TrimStart('"').TrimStart("'") + '.exe')).Trim('"')
$UninsParams = $aux[1].TrimStart('"').TrimStart("'").Trim().split(' ',[System.StringSplitOptions]::RemoveEmptyEntries)
if($aux -notlike "param 0 = *")
{
# $UninsParams = $aux[1].TrimStart('"').TrimStart("'").Trim().split(' ',[System.StringSplitOptions]::RemoveEmptyEntries)
}
$Uninstaller
$UninsParams
# . $Uninstaller $UninsParams | Where-Object { $_ -notlike "param 0 = *" }
}
}
In my example I'm trying to get an output for Zoom. I have the Zoom client installed and the Zoom Outlook plugin installed.
Here is the output of the program:
DisplayName : Zoom Outlook Plugin
PSPath : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\{0B76DE11-5937-4491-A66A-617E42170AFF}
PSParentPath : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall
PSChildName : {0B76DE11-5937-4491-A66A-617E42170AFF}
PSDrive : HKLM
PSProvider : Microsoft.PowerShell.Core\Registry
You cannot call a method on a null-valued expression.
At line:34 char:9
+ $UninsParams = $aux[1].TrimStart('"').TrimStart("'").Trim().s ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull
AuthorizedCDFPrefix :
Comments : Zoom
Contact : Zoom Video Communications, Inc.
DisplayVersion : 5.4.58891
HelpLink : https://support.zoom.us/home
HelpTelephone :
InstallDate : 20201119
InstallLocation :
InstallSource : C:\temp\Zoom\
ModifyPath : MsiExec.exe /X{3109C49B-F5E4-4FEC-8F6F-EC5E4626B361}
NoModify : 1
Publisher : Zoom
Readme :
Size :
EstimatedSize : 122109
UninstallString : MsiExec.exe /X{3109C49B-F5E4-4FEC-8F6F-EC5E4626B361}
URLInfoAbout : https://zoom.us
URLUpdateInfo :
VersionMajor : 5
VersionMinor : 4
WindowsInstaller : 1
Version : 84207115
Language : 1033
DisplayName : Zoom
PSPath : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\{3109C49B-F5E4-4FEC-8F6F-EC5E4626B36
1}
PSParentPath : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall
PSChildName : {3109C49B-F5E4-4FEC-8F6F-EC5E4626B361}
PSDrive : HKLM
PSProvider : Microsoft.PowerShell.Core\Registry
Part of the problem from what I can tell is the Zoom Outlook plugin doesn't have any uninstall strings associated with it. I'm assuming it's just part of the Zoom Client (even though it's a seperate installer). What I'm trying to do is get this code to work without throwing any errors or displaying false positives.
Here is the output of my 2 parms "$Uninstaller" and "$UninsParams"
You cannot call a method on a null-valued expression.
At line:34 char:9
+ $UninsParams = $aux[1].TrimStart('"').TrimStart("'").Trim().s ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull
.exe
/X{3109C49B-F5E4-4FEC-8F6F-EC5E4626B361}
MsiExec.exe
/X{3109C49B-F5E4-4FEC-8F6F-EC5E4626B361}
Thanks in advance!

Answer 1

The problem here is that since the Zoom Client Plugin doesn't have an uninstall script, your -split operation evaluates to a single empty string, and $aux[1] therefore evaluates to $null, hence the error message.
You could filter out entries without a valid UninstallString:
foreach($Program in $Programs |Where-Object UninstallString -match '\.exe')
{
# ... now you don't need to worry about this not resulting in two strings
$aux = $ProgUninstall -split #('\.exe'),2,[System.StringSplitOptions]::None
}