diff folders

$folder1 = "C:\path\to\first\folder"
$folder2 = "C:\path\to\second\folder"

$hash1 = Get-ChildItem $folder1 -Recurse | Get-FileHash | Select-Object Hash, Path 
$hash2 = Get-ChildItem $folder2 -Recurse | Get-FileHash | Select-Object Hash, Path

$diff1 = Compare-Object $hash1 $hash2 -Property Hash -PassThru | Where-Object { $_.SideIndicator -eq "<=" }
$diff2 = Compare-Object $hash1 $hash2 -Property Hash -PassThru | Where-Object { $_.SideIndicator -eq "=>" }

Write-Host "Files in folder 1 not in folder 2:"
$diff1 | ForEach-Object { $_.Path }

Write-Host "Files in folder 2 not in folder 1:"
$diff2 | ForEach-Object { $_.Path }