Avast Free Antivirus Silent Uninstall (PowerShell)

This article will serve as an informative guide and give you a clear understanding of how to perform silent or interactive uninstalls of Avast Free Antivirus using the Powershell App Deployment Toolkit. The PowerShell App Deployment Toolkit can be used to replace your WiseScript, VBScript and Batch wrapper scripts with one versatile, re-usable and extensible tool. This tool is an absolute must for Microsoft Endpoint Manager Configuration Manager (MEMCM) / (SCCM) Administrators or anyone who is responsible for packaging and deploying software.

How to Uninstall Avast Free Antivirus Using the PowerShell App Deployment Toolkit

  1. Download the Powershell App Deployment Toolkit 3.8.4:
  2. Download the zip file to a folder created at (C:\Downloads)
  3. Open Windows PowerShell by Right-Clicking on Windows PowerShell and selecting Run as Administrator
  4. Enter the following command to remove the Zone.Identifier:
    • Unblock-File -Path C:\Downloads\PSAppDeployToolkit_v3.8.4.zip
  5. Enter the following command to extract the contents of the zip file:
    • Expand-Archive -Path C:\Downloads\PSAppDeployToolkit_v3.8.4.zip -DestinationPath C:\Downloads\PADT
  6. Enter the following commands to copy the AppDeployToolkit folder to “C:\Downloads\Uninstall-AvastFree:
    • Copy-Item -Path "C:\Downloads\PADT\Toolkit\AppDeployToolkit" -Destination "C:\Downloads\Uninstall-AvastFree\AppDeployToolkit" -Recurse

You should now see the AppDeploymentToolkit folder with files at “C:\Downloads\Uninstall-AvastFree”

  • Copy the PowerShell script below to “C:\Downloads\Uninstall-AvastFree & name it Uninstall-AvastFree.ps1
<#
.SYNOPSIS
	This script performs the uninstallation of Avast Free Antivirus.
	# LICENSE #
	PowerShell App Deployment Toolkit - Provides a set of functions to perform common application deployment tasks on Windows.
	Copyright (C) 2017 - Sean Lillis, Dan Cunningham, Muhammad Mashwani, Aman Motazedian.
	This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
	You should have received a copy of the GNU Lesser General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.
.DESCRIPTION
	The script is provided as a template to perform an install or uninstall of an application(s).
	The script either performs an "Install" deployment type or an "Uninstall" deployment type.
	The install deployment type is broken down into 3 main sections/phases: Pre-Install, Install, and Post-Install.
	The script dot-sources the AppDeployToolkitMain.ps1 script which contains the logic and functions required to install or uninstall an application.
.PARAMETER DeploymentType
	The type of deployment to perform. Default is: Install.
.PARAMETER DeployMode
	Specifies whether the installation should be run in Interactive, Silent, or NonInteractive mode. Default is: Interactive. Options: Interactive = Shows dialogs, Silent = No dialogs, NonInteractive = Very silent, i.e. no blocking apps. NonInteractive mode is automatically set if it is detected that the process is not user interactive.
.PARAMETER AllowRebootPassThru
	Allows the 3010 return code (requires restart) to be passed back to the parent process (e.g. SCCM) if detected from an installation. If 3010 is passed back to SCCM, a reboot prompt will be triggered.
.PARAMETER TerminalServerMode
	Changes to "user install mode" and back to "user execute mode" for installing/uninstalling applications for Remote Destkop Session Hosts/Citrix servers.
.PARAMETER DisableLogging
	Disables logging to file for the script. Default is: $false.
.EXAMPLE
    PowerShell.exe .\Uninstall-AvastFree.ps1 -DeploymentType "Uninstall" -DeployMode "NonInteractive"
.EXAMPLE
    PowerShell.exe .\Uninstall-AvastFree.ps1 -DeploymentType "Uninstall" -DeployMode "Silent"
.EXAMPLE
    PowerShell.exe .\Uninstall-AvastFree.ps1 -DeploymentType "Uninstall" -DeployMode "Interactive"
.NOTES
	Toolkit Exit Code Ranges:
	60000 - 68999: Reserved for built-in exit codes in Deploy-Application.ps1, Deploy-Application.exe, and AppDeployToolkitMain.ps1
	69000 - 69999: Recommended for user customized exit codes in Deploy-Application.ps1
	70000 - 79999: Recommended for user customized exit codes in AppDeployToolkitExtensions.ps1
.LINK
	http://psappdeploytoolkit.com
#>
[CmdletBinding()]
Param (
	[Parameter(Mandatory=$false)]
	[ValidateSet('Install','Uninstall','Repair')]
	[string]$DeploymentType = 'Install',
	[Parameter(Mandatory=$false)]
	[ValidateSet('Interactive','Silent','NonInteractive')]
	[string]$DeployMode = 'Interactive',
	[Parameter(Mandatory=$false)]
	[switch]$AllowRebootPassThru = $false,
	[Parameter(Mandatory=$false)]
	[switch]$TerminalServerMode = $false,
	[Parameter(Mandatory=$false)]
	[switch]$DisableLogging = $false
)

Try {
	## Set the script execution policy for this process
	Try { Set-ExecutionPolicy -ExecutionPolicy 'ByPass' -Scope 'Process' -Force -ErrorAction 'Stop' } Catch {}

	##*===============================================
	##* VARIABLE DECLARATION
	##*===============================================
	## Variables: Application
	[string]$appVendor = ''
	[string]$appName = 'Avast Free Antivirus Uninstall'
	[string]$appVersion = ''
	[string]$appArch = ''
	[string]$appLang = ''
	[string]$appRevision = ''
	[string]$appScriptVersion = '1.0.0'
	[string]$appScriptDate = 'XX/XX/20XX'
	[string]$appScriptAuthor = 'Jason Bergner'
	##*===============================================
	## Variables: Install Titles (Only set here to override defaults set by the toolkit)
	[string]$installName = ''
	[string]$installTitle = 'Avast Free Antivirus Uninstall (All Versions)'

	##* Do not modify section below
	#region DoNotModify

	## Variables: Exit Code
	[int32]$mainExitCode = 0

	## Variables: Script
	[string]$deployAppScriptFriendlyName = 'Deploy Application'
	[version]$deployAppScriptVersion = [version]'3.8.4'
	[string]$deployAppScriptDate = '26/01/2021'
	[hashtable]$deployAppScriptParameters = $psBoundParameters

	## Variables: Environment
	If (Test-Path -LiteralPath 'variable:HostInvocation') { $InvocationInfo = $HostInvocation } Else { $InvocationInfo = $MyInvocation }
	[string]$scriptDirectory = Split-Path -Path $InvocationInfo.MyCommand.Definition -Parent

	## Dot source the required App Deploy Toolkit Functions
	Try {
		[string]$moduleAppDeployToolkitMain = "$scriptDirectory\AppDeployToolkit\AppDeployToolkitMain.ps1"
		If (-not (Test-Path -LiteralPath $moduleAppDeployToolkitMain -PathType 'Leaf')) { Throw "Module does not exist at the specified location [$moduleAppDeployToolkitMain]." }
		If ($DisableLogging) { . $moduleAppDeployToolkitMain -DisableLogging } Else { . $moduleAppDeployToolkitMain }
	}
	Catch {
		If ($mainExitCode -eq 0){ [int32]$mainExitCode = 60008 }
		Write-Error -Message "Module [$moduleAppDeployToolkitMain] failed to load: `n$($_.Exception.Message)`n `n$($_.InvocationInfo.PositionMessage)" -ErrorAction 'Continue'
		## Exit the script, returning the exit code to SCCM
		If (Test-Path -LiteralPath 'variable:HostInvocation') { $script:ExitCode = $mainExitCode; Exit } Else { Exit $mainExitCode }
	}

	#endregion
	##* Do not modify section above
	##*===============================================
	##* END VARIABLE DECLARATION
	##*===============================================

	If ($deploymentType -ine 'Uninstall' -and $deploymentType -ine 'Repair') {
		##*===============================================
		##* PRE-INSTALLATION
		##*===============================================
		[string]$installPhase = 'Pre-Installation'

		##*===============================================
		##* INSTALLATION
		##*===============================================
		[string]$installPhase = 'Installation'
    
		##*===============================================
		##* POST-INSTALLATION
		##*===============================================
		[string]$installPhase = 'Post-Installation'

	}
	ElseIf ($deploymentType -ieq 'Uninstall')
	{
		##*===============================================
		##* PRE-UNINSTALLATION
		##*===============================================
		[string]$installPhase = 'Pre-Uninstallation'

		## Show Welcome Message
		Show-InstallationWelcome

        ## Show Progress Message (With a Message to Indicate the Application is Being Uninstalled)
        Show-InstallationProgress -StatusMessage "Uninstalling Any Existing Versions of Avast Free Antivirus. Please Wait..."

		##*===============================================
		##* UNINSTALLATION
		##*===============================================
		[string]$installPhase = 'Uninstallation'

        ## Uninstall Any Existing Version of Avast Free Antivirus
        $AppList = Get-InstalledApplication -Name 'Avast Free Antivirus'		
        ForEach ($App in $AppList)
        {
        If($App.UninstallString)
        {
        $InstallPath = $App.InstallLocation
        If(Test-Path -Path $InstallPath)
        {
        Write-log -Message "Found $($App.DisplayName) ($($App.DisplayVersion)), now attempting to uninstall."

        ## Make Sure Avast Self-Defense Module is Disabled
        $SelfDefense = Get-RegistryKey -Key ("HKLM:\SOFTWARE\Avast Software\Avast\properties\settings\SelfDefense")
        If ($SelfDefense.SelfDefense -ne 0) {

        Write-Log -Message "Avast Self-Defense Module is Currently Enabled. Avast Self-Defense Must be Disabled Before the Uninstall Can Proceed. Open Avast Free Antivirus-> Menu-> Settings-> Troubleshooting-> Uncheck Enable Self-Defense" -Severity 2
        Show-InstallationPrompt -Message "The Avast Self-Defense Module is Currently Enabled. Avast Self-Defense Must be Disabled Before the Uninstall Can Proceed. Open Avast Free Antivirus-> Menu-> Settings-> Troubleshooting-> Uncheck Enable Self-Defense" -ButtonRightText 'OK'
        Exit-Script -ExitCode 69005 #This code is to indicate that uninstallation cannot proceed until the self-defense module is disabled.
        }

        ElseIf ($SelfDefense.SelfDefense -eq 0) {
        Write-log -Message "Confirmed that Avast Self-Defense Module is Disabled."

        ## Update the Stat.ini to Allow Silent Uninstall
        Write-log -Message "Updating the Stat.ini to Allow Silent Uninstall."
        $StatsINI = "$InstallPath\setup\Stats.ini"
        (Get-Content -Path $StatsINI) | ForEach-Object { $_ -replace "\[Common\]", "[Common]`nSilentUninstallEnabled=1" } | Set-Content $StatsINI

        ## Uninstall Avast Free Antivirus
        Write-log -Message "Uninstalling Avast Free Antivirus."

        New-Item "$envWinDir\Temp\Avast\" -ItemType Directory -Force
        New-Item "$envWinDir\Temp\Avast\Uninstall-Avast.cmd" -ItemType File -Value '"%ProgramFiles%\Avast Software\Avast\setup\Instup.exe" /control_panel /instop:uninstall /silent /wait' -Force
        Start-Sleep -Seconds 5

        cmd /c "$envWinDir\Temp\Avast\Uninstall-Avast.cmd"
        Get-Process -Name "Instup" -ErrorAction SilentlyContinue | Wait-Process
        }
        }
        }
        }  

		##*===============================================
		##* POST-UNINSTALLATION
		##*===============================================
		[string]$installPhase = 'Post-Uninstallation'


	}
	ElseIf ($deploymentType -ieq 'Repair')
	{
		##*===============================================
		##* PRE-REPAIR
		##*===============================================
		[string]$installPhase = 'Pre-Repair'


		##*===============================================
		##* REPAIR
		##*===============================================
		[string]$installPhase = 'Repair'


		##*===============================================
		##* POST-REPAIR
		##*===============================================
		[string]$installPhase = 'Post-Repair'


    }
	##*===============================================
	##* END SCRIPT BODY
	##*===============================================

	## Call the Exit-Script function to perform final cleanup operations
	Exit-Script -ExitCode $mainExitCode
}
Catch {
	[int32]$mainExitCode = 60001
	[string]$mainErrorMessage = "$(Resolve-Error)"
	Write-Log -Message $mainErrorMessage -Severity 3 -Source $deployAppScriptFriendlyName
	Show-DialogBox -Text $mainErrorMessage -Icon 'Stop'
	Exit-Script -ExitCode $mainExitCode
}

Ok, all the hard work is done and now you can uninstall any version of Avast Free Antivirus using one single PowerShell script. Logging functionality is built-in automatically and you can view the log files under “C:\Windows\Logs\Software”


Avast Free Antivirus NonInteractive Uninstall (PowerShell)

NonInteractive means Very Silent, i.e. no blocking apps. This is automatically set if it is detected that the process is not running in the user session and it is not possible for anyone to provide input using a mouse or keyboard.

  • Open Windows PowerShell by Right-Clicking on Windows PowerShell and selecting Run as Administrator
  • Change the directory to “C:\Downloads\Uninstall-AvastFree
    • PS C:\Downloads\Uninstall-AvastFree>
  • Enter the following command:
Powershell.exe -ExecutionPolicy Bypass .\Uninstall-AvastFree.ps1 -DeploymentType "Uninstall" -DeployMode "NonInteractive"

Avast Free Antivirus Silent Uninstall (PowerShell)

Silent means no dialogs (progress and balloon tip notifications are suppressed).

  • Open Windows PowerShell by Right-Clicking on Windows PowerShell and selecting Run as Administrator
  • Change the directory to “C:\Downloads\Uninstall-AvastFree
    • PS C:\Downloads\Uninstall-AvastFree>
  • Enter the following command:
Powershell.exe -ExecutionPolicy Bypass .\Uninstall-AvastFree.ps1 -DeploymentType "Uninstall" -DeployMode "Silent"

Avast Free Antivirus Interactive Uninstall (PowerShell)

Interactive means the install will show dialogs including progress and balloon tip notifications.

  • Open Windows PowerShell by Right-Clicking on Windows PowerShell and selecting Run as Administrator
  • Change the directory to “C:\Downloads\Uninstall-AvastFree
    • PS C:\Downloads\Uninstall-AvastFree>
  • Enter the following command:
Powershell.exe -ExecutionPolicy Bypass .\Uninstall-AvastFree.ps1 -DeploymentType "Uninstall" -DeployMode "Interactive"

Always make sure to test everything in a development environment prior to implementing anything into production. The information in this article is provided “As Is” without warranty of any kind.