PowerShell扫描超长路径文件报错，无法获取完整列表求解决

我需要构建日志记录服务器中路径长度超过255字符的文件，当前PowerShell脚本能识别最长351字符的文件，已找到780个超限制文件，但执行结束时出现大量报错，提示未获取完整列表。

现有脚本 #

# The path to scan and the the lengths for (sub-directories will be scanned as well).
$pathToScan = "\\Server\\"          #or "\\Server\\Share\\" 

# This must be a file in a directory that exists and does not require admin rights to write to.
$outputFilePath = "C:\temp\FilePathLengths.txt" 

$Drive = New-PSDrive "X" -PSProvider FileSystem -Root $pathToScan
$DriveLength = $pathToScan.Length

$writeToConsoleAsWell = $false   # Writing to the console will be much slower.
 
# Open a new file stream and write all the paths and their lengths to it.
$outputFileDirectory = Split-Path $outputFilePath -Parent

if (!(Test-Path $outputFileDirectory)) { New-Item $outputFileDirectory -ItemType Directory }
$stream = New-Object System.IO.StreamWriter($outputFilePath, $false)

# Starting effort before this caused errors, tried alternatives
# Get-ChildItem -Path $pathToScan -Recurse -Force | Select-Object -Property FullName, @{Name="FullNameLength";Expression={($_.FullName.Length)}} | Sort-Object -Property FullNameLength -Descending | ForEach-Object {

Get-ChildItem -Path "X:\" -Recurse -Force | Select-Object -Property FullName, @{Name="FullNameLength";Expression={($_.FullName.Length)}} | Sort-Object -Property FullNameLength -Descending | ForEach-Object {
    If ($_.FullNameLength -gt 255) {
    $filePath = $_.FullName
    $length = $_.FullNameLength
    $string = "$length | $filePath"
     
    # Write to the Console.
    if ($writeToConsoleAsWell) { Write-Host $string }
  
    #Write to the file.
    $stream.WriteLine($string)
    }
}
$stream.Close()
Remove-PSDrive "X"

报错信息 #

Get-ChildItem : 指定的路径、文件名或两者过长。完全限定的文件名必须少于260个字符，目录名必须少于248个字符。
At 'ScriptPath&Name'.ps1:17 char:1
- Get-ChildItem -Path "X:" -Recurse -Force | Select-Object -Property F ...
- 
  + CategoryInfo          : ReadError: ('FilePath that isn't descriptive enough to actually identify the file' :String) [Get-ChildItem], PathTooLongException
  + FullyQualifiedErrorId : DirIOError,Microsoft.PowerShell.Commands.GetChildItemCommand

需求目标 #

我的目标是识别所有VEEAM/VMware在从Server 2012迁移到2022时可能无法正确处理或恢复的目录项，以便批量或单独处理。我已尝试在注册表中启用长路径、使用临时PSDrive缩短路径，但仍有超过350字符的路径触发报错，希望能获取完整的超长路径文件分析结果。

解决方案 #

1. 改用.NET原生长路径API扫描 #

PowerShell的Get-ChildItem依赖传统Win32 API，即使启用长路径支持，递归扫描时仍可能触发路径过长错误。改用.NET的System.IO.Directory类方法，原生支持长路径解析：

# 配置参数
$pathToScan = "\\Server\"
$outputFilePath = "C:\temp\FilePathLengths.txt"
$lengthThreshold = 255

# 创建输出目录（如果不存在）
$outputDir = Split-Path $outputFilePath -Parent
if (-not (Test-Path $outputDir)) {
    New-Item $outputDir -ItemType Directory | Out-Null
}

# 使用.NET API递归获取所有文件和目录
$allItems = @()
# 扫描所有文件
$allItems += [System.IO.Directory]::EnumerateFiles($pathToScan, "*", [System.IO.SearchOption]::AllDirectories)
# 扫描所有目录
$allItems += [System.IO.Directory]::EnumerateDirectories($pathToScan, "*", [System.IO.SearchOption]::AllDirectories)

# 筛选超长路径并写入文件
$stream = New-Object System.IO.StreamWriter($outputFilePath, $false)
foreach ($item in $allItems) {
    $pathLength = $item.Length
    if ($pathLength -gt $lengthThreshold) {
        $stream.WriteLine("$pathLength | $item")
    }
}
$stream.Close()

2. 确保系统长路径支持生效 #

• 注册表设置：在HKLM\SYSTEM\CurrentControlSet\Control\FileSystem下，将LongPathsEnabled（DWORD）设置为1，重启系统后生效
• 环境要求：PowerShell需基于.NET Framework 4.6.2+或.NET Core（Server 2022默认满足）
• SMB共享：确保源服务器（Server 2012）和目标服务器（Server 2022）均启用长路径支持

3. 处理极端超长路径（超过32767字符） #

若存在超过32767字符的路径，可添加\\?\前缀强制启用最大长度路径解析：

$longPathPrefix = "\\?\"
# 转换为绝对路径并添加前缀
$fullScanningPath = $longPathPrefix + ([System.IO.Path]::GetFullPath($pathToScan))

# 使用带前缀的路径扫描
$allItems = [System.IO.Directory]::EnumerateFiles($fullScanningPath, "*", [System.IO.SearchOption]::AllDirectories)
$allItems += [System.IO.Directory]::EnumerateDirectories($fullScanningPath, "*", [System.IO.SearchOption]::AllDirectories)

4. 脚本性能优化 #

• 禁用控制台输出：保持$writeToConsoleAsWell = $false，避免IO开销拖慢扫描速度
• 使用StreamWriter：相比Out-File或Add-Content，直接写入文件流能大幅提升写入效率

内容的提问来源于stack exchange，提问作者Jeremy