Windows 无法设置默认打印机 0x00000709：不是驱动坏了，是注册表里有一条死记录

#Requires -Version 5.1
<#
.SYNOPSIS
    Windows 0x00000709「无法设置默认打印机」排障工具

.DESCRIPTION
    四种动作：
      Detect      只读检测：当前默认打印机、注册表 Device 值、自动管理开关、残留判断
      SetDefault  用 COM 接口设置默认打印机（绕过设置界面，专治界面点不动的场景）
      Repair      备份并清理残留 Device 值 + 关闭"让 Windows 管理默认打印机" + 重启 Spooler
      Rollback    还原 Repair 的改动

.PARAMETER Action
    要执行的动作，默认 Detect。

.PARAMETER PrinterName
    SetDefault 时使用的打印机名称，必须与 Get-Printer 输出完全一致。

.EXAMPLE
    .\Fix-DefaultPrinter0709.ps1 -Action Detect

.EXAMPLE
    .\Fix-DefaultPrinter0709.ps1 -Action SetDefault -PrinterName "3F-HP-M403"

.EXAMPLE
    .\Fix-DefaultPrinter0709.ps1 -Action Repair -WhatIf

.NOTES
    最后更新：2026-10-20
    适用：Windows 10 1803+ / Windows 11；PowerShell 5.1 与 7 均可
#>

[CmdletBinding(SupportsShouldProcess = $true, ConfirmImpact = 'Medium')]
param(
    [ValidateSet('Detect', 'SetDefault', 'Repair', 'Rollback')]
    [string]$Action = 'Detect',

    [string]$PrinterName
)

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'

$WinKey    = 'HKCU:\Software\Microsoft\Windows NT\CurrentVersion\Windows'
$SvcName   = 'Spooler'
$BackupDir = Join-Path $env:TEMP 'itdb-0709'
$BackupFile = Join-Path $BackupDir 'device-backup.txt'

function Write-Head([string]$text) {
    Write-Host ''
    Write-Host $text -ForegroundColor Yellow
    Write-Host ('-' * 34) -ForegroundColor DarkGray
}

function Get-DefaultPrinterName {
    $p = Get-CimInstance -ClassName Win32_Printer -Filter 'Default = TRUE' -ErrorAction SilentlyContinue
    if ($null -eq $p) { return $null }
    return $p.Name
}

function Get-DeviceValue {
    $item = Get-ItemProperty -Path $WinKey -Name 'Device' -ErrorAction SilentlyContinue
    if ($null -eq $item) { return $null }
    $value = $item.Device
    if ([string]::IsNullOrWhiteSpace($value)) { return $null }
    return $value
}

function Get-ManagedDefaultValue {
    $item = Get-ItemProperty -Path $WinKey -Name 'LegacyDefaultPrinterMode' -ErrorAction SilentlyContinue
    if ($null -eq $item) { return $null }
    return $item.LegacyDefaultPrinterMode
}

function Restart-SpoolerInternal {
    Write-Host '   -> 重启打印后台处理程序 (Spooler) ...'
    Restart-Service -Name $SvcName -Force
    $svc = Get-Service -Name $SvcName
    Write-Host ("   -> Spooler 当前状态：{0}" -f $svc.Status)
}

# ---------------------------------------------------------------- Detect

function Invoke-Detect {
    [CmdletBinding(SupportsShouldProcess = $true)]
    param()

    Write-Head '[1/5] 系统信息'
    $os = Get-CimInstance -ClassName Win32_OperatingSystem
    Write-Host ("   系统：{0}  Build {1}" -f $os.Caption, $os.BuildNumber)
    Write-Host ("   计算机：{0}   域/组：{1}" -f $env:COMPUTERNAME, $env:USERDOMAIN)
    $svc = Get-Service -Name $SvcName
    Write-Host ("   Spooler：{0}  启动类型：{1}" -f $svc.Status, $svc.StartType)

    Write-Head '[2/5] 当前打印机清单'
    $printers = @()
    $readOk = $false
    try {
        $printers = @(Get-Printer -ErrorAction Stop)
        $readOk = $true
        if ($printers.Count -eq 0) {
            Write-Host '   本机没有任何打印机' -ForegroundColor Gray
        }
        foreach ($p in $printers) {
            $mark = if ($p.Name -eq (Get-DefaultPrinterName)) { ' [默认]' } else { '' }
            Write-Host ("   - {0}{1}" -f $p.Name, $mark) -ForegroundColor $(if ($mark) { 'Green' } else { 'Gray' })
            Write-Host ("     端口：{0}   驱动：{1}" -f $p.PortName, $p.DriverName) -ForegroundColor DarkGray
        }
    }
    catch {
        Write-Host '   读取打印机列表失败（这不等于没有打印机）' -ForegroundColor Red
        Write-Host ("   原因：{0}" -f $_.Exception.Message) -ForegroundColor DarkGray
    }

    Write-Head '[3/5] 注册表默认打印机记录 (Device)'
    $device = Get-DeviceValue
    if ($null -eq $device) {
        Write-Host '   Device：<未设置>' -ForegroundColor Gray
    }
    else {
        Write-Host ("   Device：{0}" -f $device)
        Write-Host '   格式说明：打印机名,winspool,端口名' -ForegroundColor DarkGray
    }

    Write-Head '[4/5] Windows 默认打印机管理'
    $managed = Get-ManagedDefaultValue
    if ($null -eq $managed) {
        Write-Host '   LegacyDefaultPrinterMode：<未设置>（由 Windows 自动管理默认打印机）' -ForegroundColor Gray
    }
    elseif ($managed -eq 1) {
        Write-Host '   LegacyDefaultPrinterMode：1（已关闭自动管理，由用户手动指定）' -ForegroundColor Green
    }
    else {
        Write-Host ("   LegacyDefaultPrinterMode：{0}（自动管理仍生效）" -f $managed)
    }

    Write-Head '[5/5] 诊断建议'
    if (-not $readOk) {
        Write-Host '   无法读取打印机清单，本次不做判断。' -ForegroundColor Red
        Write-Host '   请先确保：① 以管理员身份运行  ② Spooler 服务已启动，然后重新执行 Detect。' -ForegroundColor Red
        return
    }
    if ($printers.Count -eq 0) {
        Write-Host '   本机没有打印机，先添加打印机再谈默认值。' -ForegroundColor Red
        return
    }

    $stale = $false
    if ($null -ne $device) {
        $devName = ($device -split ',')[0]
        $exists = @($printers | Where-Object { $_.Name -eq $devName }).Count -gt 0
        if (-not $exists) {
            $stale = $true
            Write-Host ("   !! 残留记录：Device 指向的「{0}」已不存在" -f $devName) -ForegroundColor Red
            Write-Host '      这就是 0x00000709 最常见的原因 —— 设默认时写不进这条记录。' -ForegroundColor Red
        }
        else {
            Write-Host ("   Device 指向的「{0}」存在，记录正常。" -f $devName) -ForegroundColor Green
        }
    }

    if ((Get-DefaultPrinterName) -eq $null) {
        Write-Host '   !! 当前没有默认打印机' -ForegroundColor Red
    }

    if ($stale) {
        Write-Host ''
        Write-Host '   建议执行：-Action Repair  （先预览：-Action Repair -WhatIf）' -ForegroundColor Cyan
    }
    else {
        Write-Host ''
        Write-Host '   建议先用命令行直接设默认：-Action SetDefault -PrinterName "打印机名"' -ForegroundColor Cyan
        Write-Host '   若界面里点"设为默认"仍报 0x00000709，再执行 Repair。' -ForegroundColor Cyan
    }
}

# ---------------------------------------------------------------- SetDefault

function Invoke-SetDefault {
    [CmdletBinding(SupportsShouldProcess = $true)]
    param()

    if ([string]::IsNullOrWhiteSpace($PrinterName)) {
        throw '需要 -PrinterName 参数。先用 -Action Detect 查看准确的打印机名称。'
    }
    $target = Get-Printer -Name $PrinterName -ErrorAction SilentlyContinue
    if ($null -eq $target) {
        throw ("本机没有名为 '{0}' 的打印机。请用 -Action Detect 核对名称。" -f $PrinterName)
    }

    Write-Head ("设置默认打印机：{0}" -f $PrinterName)

    if ($PSCmdlet.ShouldProcess($PrinterName, '设为默认打印机')) {
        $ok = $false
        try {
            $net = New-Object -ComObject WScript.Network
            $net.SetDefaultPrinter($PrinterName)
            $ok = $true
        }
        catch {
            Write-Host ("   COM 方式失败：{0}" -f $_.Exception.Message) -ForegroundColor DarkGray
        }

        Start-Sleep -Milliseconds 300
        $now = Get-DefaultPrinterName
        if ($now -ne $PrinterName) {
            Write-Host '   COM 方式未生效，改用 printui.dll ...' -ForegroundColor Yellow
            $null = & rundll32.exe printui.dll,PrintUIEntry /y /n $PrinterName
            Start-Sleep -Milliseconds 500
            $now = Get-DefaultPrinterName
        }

        if ($now -eq $PrinterName) {
            Write-Host ("   -> 成功，当前默认打印机：{0}" -f $now) -ForegroundColor Green
        }
        else {
            Write-Host ("   -> 失败，当前默认打印机仍为：{0}" -f $now) -ForegroundColor Red
            Write-Host '      请尝试 -Action Repair 清理残留记录后重试。' -ForegroundColor Red
        }
    }
    else {
        Write-Host '   -> [WhatIf] 预览模式，未做任何修改。' -ForegroundColor Yellow
    }
}

# ---------------------------------------------------------------- Repair

function Invoke-Repair {
    [CmdletBinding(SupportsShouldProcess = $true)]
    param()

    Write-Head '清理残留 Device 记录 + 关闭自动管理默认打印机'

    $device = Get-DeviceValue
    $managed = Get-ManagedDefaultValue

    if ($null -ne $device -or $null -ne $managed) {
        if (-not (Test-Path -Path $BackupDir)) {
            if ($PSCmdlet.ShouldProcess($BackupDir, '创建备份目录')) {
                New-Item -ItemType Directory -Path $BackupDir -Force | Out-Null
            }
        }
        $backup = "Device=$device`r`nLegacyDefaultPrinterMode=$managed`r`nSavedAt=$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')"
        if ($PSCmdlet.ShouldProcess($BackupFile, '写入改动前备份')) {
            $backup | Out-File -FilePath $BackupFile -Encoding utf8
            Write-Host ("   -> 已备份原值到 {0}" -f $BackupFile) -ForegroundColor Green
        }
    }

    if ($null -ne $device) {
        if ($PSCmdlet.ShouldProcess("$WinKey\Device", '删除残留值')) {
            Remove-ItemProperty -Path $WinKey -Name 'Device' -Force
            Write-Host '   -> 已删除 Device（残留记录）' -ForegroundColor Green
        }
        else {
            Write-Host '   -> [WhatIf] 将删除 Device 残留记录' -ForegroundColor Yellow
        }
    }
    else {
        Write-Host '   Device 本来就为空，跳过' -ForegroundColor Gray
    }

    if ($PSCmdlet.ShouldProcess("$WinKey\LegacyDefaultPrinterMode", '设置为 1（关闭自动管理）')) {
        New-ItemProperty -Path $WinKey -Name 'LegacyDefaultPrinterMode' -PropertyType DWord -Value 1 -Force | Out-Null
        Write-Host '   -> 已关闭「让 Windows 管理默认打印机」' -ForegroundColor Green
    }
    else {
        Write-Host '   -> [WhatIf] 将把 LegacyDefaultPrinterMode 设为 1' -ForegroundColor Yellow
    }

    if ($PSCmdlet.ShouldProcess($SvcName, '重启打印后台处理程序')) {
        Restart-SpoolerInternal
    }
    else {
        Write-Host '   -> [WhatIf] 将重启 Spooler' -ForegroundColor Yellow
    }

    Write-Host ''
    if ($WhatIfPreference) {
        Write-Host '   [WhatIf] 预览结束，未做任何修改。去掉 -WhatIf 即真实执行。' -ForegroundColor Yellow
    }
    else {
        Write-Host '   完成。请重新设置默认打印机：-Action SetDefault -PrinterName "打印机名"' -ForegroundColor Cyan
        Write-Host '   如果没生效，注销并重新登录一次（HKCU 改动需要会话重载）。' -ForegroundColor Cyan
    }
}

# ---------------------------------------------------------------- Rollback

function Invoke-Rollback {
    [CmdletBinding(SupportsShouldProcess = $true)]
    param()

    Write-Head '还原 Repair 的改动'
    if (-not (Test-Path -Path $BackupFile)) {
        Write-Host ("   没找到备份文件：{0}" -f $BackupFile) -ForegroundColor Red
        Write-Host '   未做过 Repair，或备份已被清理，无需回滚。' -ForegroundColor Gray
        return
    }

    $raw = Get-Content -Path $BackupFile -Raw
    Write-Host '   备份内容：'
    Write-Host ('   ' + ($raw -replace "`r`n", "`r`n   ")) -ForegroundColor DarkGray

    if ($PSCmdlet.ShouldProcess($WinKey, '移除 LegacyDefaultPrinterMode 并重启 Spooler')) {
        Remove-ItemProperty -Path $WinKey -Name 'LegacyDefaultPrinterMode' -ErrorAction SilentlyContinue
        Write-Host '   -> 已移除 LegacyDefaultPrinterMode，恢复自动管理' -ForegroundColor Green
        Restart-SpoolerInternal
        Write-Host '   注意：Device 值不自动写回 —— 写回一条旧记录反而会重新制造问题。' -ForegroundColor Yellow
        Write-Host '   如需恢复默认打印机，请用 -Action SetDefault 重新指定。' -ForegroundColor Yellow
    }
    else {
        Write-Host '   -> [WhatIf] 预览模式，未做任何修改。' -ForegroundColor Yellow
    }
}

# ---------------------------------------------------------------- 入口

Write-Host ''
Write-Host '0x00000709 默认打印机排障工具  |  只读检测请用 -Action Detect' -ForegroundColor Cyan
Write-Host ("当前动作：{0}" -f $Action) -ForegroundColor Cyan

switch ($Action) {
    'Detect'     { Invoke-Detect -WhatIf:$WhatIfPreference }
    'SetDefault' { Invoke-SetDefault -WhatIf:$WhatIfPreference }
    'Repair'     { Invoke-Repair -WhatIf:$WhatIfPreference }
    'Rollback'   { Invoke-Rollback -WhatIf:$WhatIfPreference }
}

Write-Host ''
Write-Host '完成。' -ForegroundColor Cyan