ClearTeamsClientCache.ps1

<#
    .SYNOPSIS
    Clears the Teams client cache on Windows machines.

    .DESCRIPTION
    Clears the Teams client cache for whichever Teams version is currently in use while retaining the custom backgrounds.

    Authors:            Martin Heusser | MVP
    Version:            1.0.1
    Changelog:          2023-12-01: Initial release

    .PARAMETER Name
        None.

    .INPUTS
        None.

    .OUTPUTS
        None.

    .EXAMPLE
    . .\ClearTeamsClientCache.ps1

#>

function Clear-TeamsCache {
    param (
        [string]$Version = "ms-teams"
    )

    if ($Version -eq "ms-teams") {
        $cachePath = "$env:LOCALAPPDATA\Packages\MSTeams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams"
    }
    elseif ($Version -eq "Teams") {
        $cachePath = "$env:APPDATA\Microsoft\Teams"
    }
    
    $backgroundsPath = "$cachePath\Backgrounds\Uploads"

    Write-Host "$Version is in use" -ForegroundColor Cyan
    Write-Host "Saving Custom Backgrounds" -ForegroundColor Cyan

    $backgrounds = Get-ChildItem -Path $backgroundsPath -ErrorAction SilentlyContinue
    $tempFiles = @()
    foreach ($background in $backgrounds) {
        $tempFiles += @{
            FileName    = $background.Name
            FullName    = $background.FullName
            FileContent = [System.IO.File]::ReadAllBytes($background.FullName)
        }
    }

    Write-Host "Remove Cache" -ForegroundColor Cyan
    Remove-Item -Path $cachePath -Recurse -Force

    Write-Host "Add Custom Backgrounds" -ForegroundColor Cyan
    New-Item -Path $cachePath -ItemType Directory | Out-Null
    New-Item -Path "$cachePath\Backgrounds" -ItemType Directory | Out-Null
    New-Item -Path $backgroundsPath -ItemType Directory | Out-Null

    foreach ($tempFile in $tempFiles) {
        [System.IO.File]::WriteAllBytes($tempFile.FullName, $tempFile.FileContent)
    }
}


if (!(Test-Path -Path "$env:APPDATA\Microsoft\Teams") -and !(Test-Path -Path "$env:LOCALAPPDATA\Packages\MSTeams_8wekyb3d8bbwe")) {
    Write-Host "Cache folders for either Teams version could not be found." -ForegroundColor Magenta
    Read-Host "Press any key to exit..."
    Exit
} else {

    $teamsProcesses = Get-Process -Name *Teams*
    if ($teamsProcesses) {
        Write-Host "Stopping Teams processes..." -ForegroundColor Magenta
        foreach ($process in $teamsProcesses) {
            Stop-Process -Id $process.Id -ErrorAction SilentlyContinue
        }

        Start-Sleep -Seconds 10

        switch ($teamsProcesses[0].ProcessName) {
            "ms-teams" {
                Clear-TeamsCache -Version $teamsProcesses[0].ProcessName       
                Write-Host "Start new Teams" -ForegroundColor Cyan
                Start-Process ms-teams.exe

            }

            "Teams" {
                Clear-TeamsCache -Version $teamsProcesses[0].ProcessName      
                Write-Host "Start old Teams" -ForegroundColor Cyan
                Set-Location "$env:LOCALAPPDATA\Microsoft\Teams"
                Start-Process -File "$env:LOCALAPPDATA\Microsoft\Teams\Update.exe" -ArgumentList '--processStart "Teams.exe"'
            }

            Default {
            }
        }
    } else {

        Write-Host "Neither version of Teams is running. Please start Teams and run this script again." -ForegroundColor Magenta
        $checkIfNewTeamsIsInstalled = (Test-Path -Path "$env:LOCALAPPDATA\Packages\MSTeams_8wekyb3d8bbwe")
        if ($checkIfNewTeamsIsInstalled -eq $true) {
            Write-Host "New Teams is installed" -ForegroundColor Cyan
            $oldTeamsLastAccessTime = Get-ItemProperty -Path "$env:LOCALAPPDATA\Microsoft\Teams\Current\Teams.exe" -ErrorAction SilentlyContinue | Select-Object -ExpandProperty LastAccessTimeUtc
            $newTeamsLogs = (Get-ChildItem -Path "$env:LOCALAPPDATA\Packages\MSTeams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams\Logs" -File -Filter "MSTeams_*.log")[-1]
            $newTeamsLogContent = Get-Content -Path $newTeamsLogs.FullName | Out-String
            $newTeamsVersionPattern = "LatestVersion:\s*(\d+(\.\d+)*)"
            $match = [regex]::Match($newTeamsLogContent, $newTeamsVersionPattern)
            $versionNumber = $match.Groups[1].Value
            $newTeamsLastAccessTime = Get-ItemProperty -Path "C:\Program Files\WindowsApps\MSTeams_$($versionNumber)_x64__8wekyb3d8bbwe\ms-teams.exe" -ErrorAction SilentlyContinue | Select-Object -ExpandProperty LastAccessTimeUtc

            if (!$oldTeamsLastAccessTime -and !$newTeamsLastAccessTime) {
                Write-Host "Teams is not installed. Could not get last used time of either Teams version." -ForegroundColor Magenta
                $lastUsedVersion = "Teams is not installed."
            } elseif ($newTeamsLastAccessTime -gt $oldTeamsLastAccessTime) {
                $lastUsedVersion = "New Teams"
            } else {
                $lastUsedVersion = "Old Teams"
            }
        } else {
            Write-Host "New Teams is not installed"
            $lastUsedVersion = "Old Teams"
        }
        Write-Host "Last used Teams version: $lastUsedVersion" -ForegroundColor Cyan
    }
}