How can I compare two folders to find missing files?

If you want something more visual than command line, check out Beyond Compare from Scooter Software. It’s not PowerShell, but it can be scripted and is by far the best comparison tool I’ve used!

Have you tried running any code yet? It might help if you share what you've implemented so far so others can give targeted help.

You can use PowerShell to compare the two folders easily. Just use these commands:

```powershell
$SourceFiles = Get-ChildItem -path $SourcePath -Recurse
$TargetFiles = Get-ChildItem -path $TargetPath -Recurse
$Missing = Compare-Object -ReferenceObject $SourceFiles -DifferenceObject $TargetFiles -Property BaseName
```

This will help you identify which files from your source are missing in the target.

Here’s a neat little script that might work for you:

```powershell
$folderA = "C:filesFolderA"
$folderB = "C:filesFolderB"

function Get-RelativePathNoExt {
param ([string]$basePath, [string]$fullPath)
$relativePath = $fullPath.Substring($basePath.Length).TrimStart('')
[System.IO.Path]::ChangeExtension($relativePath, $null)
}

$filesA = Get-ChildItem -Path $folderA -Recurse -File
$filesB = Get-ChildItem -Path $folderB -Recurse -File

$setA = $filesA | ForEach-Object { Get-RelativePathNoExt -basePath $folderA -fullPath $_.FullName }
$setB = $filesB | ForEach-Object { Get-RelativePathNoExt -basePath $folderB -fullPath $_.FullName }

diff = $setB | Where-Object { $_ -notin $setA }

Write-Host "Files in $folderA but not in $folderB :"
$diff | ForEach-Object { Write-Host $_ }
```

This should give you a list of files that are missing in your output folder.