$VMs = Get-VM 

$Toolsconfig = New-Object VMware.Vim.VirtualMachineConfigSpec
$Toolsconfig.tools = New-Object VMware.Vim.ToolsConfigInfo
$Toolsconfig.tools.toolsUpgradePolicy = "manual"

foreach ($VM in $VMs) {
    $cur = ($vm | Get-View).config.Tools.ToolsUpgradepolicy
    if ($cur -ne "manual") {
        Write-Warning "$($VM.name) - Changing VMware Tools update policy to manual from $cur"
        ($VM | Get-View).ReconfigVM($Toolsconfig)
    } else {
        Write-host "$($VM.name) - VMware Tools update policy already $cur"
    }

}