diff --git a/scripts/diagnostics/Capture-MclCache.ps1 b/scripts/diagnostics/Capture-MclCache.ps1
index 007bfae..4f8ff33 100644
--- a/scripts/diagnostics/Capture-MclCache.ps1
+++ b/scripts/diagnostics/Capture-MclCache.ps1
@@ -19,11 +19,16 @@
             files\        copies of the small text files (*.json, *.xml,
                           *.tag, *.txt, *.ini, *.log, *.cmd, *.ps1, *.bat)
                           under 5 MB, same relative paths
-        mcl-capture-<label>-<timestamp>.zip
+            SHA256SUMS    hash of every file above, for checking the copy
+
+    Then it robocopies that folder to -CopyTo (default Z:\mcl-capture, the
+    dev box pxe-images share), hashes every copied file back through the
+    share and compares with SHA256SUMS. No zip: archives arrive empty on
+    that share. The dev box can re-check with: sha256sum -c SHA256SUMS
 
     Nothing large is copied: no WIM, driver, MSU or installer. Text copies
-    have any Azure SAS signature (sig=...) blanked, so the zip carries no
-    storage credential. Read-only on the cache; needs no admin rights.
+    have any Azure SAS signature (sig=...) blanked, so the capture carries
+    no storage credential. Read-only on the cache; needs no admin rights.
 
 .PARAMETER Label
     Short name for this run, for example pro or ltsc.
@@ -34,11 +39,16 @@
 .PARAMETER OutDir
     Where to write the capture. Default: the current user's Desktop, or
     this script's folder when there is no Desktop.
+
+.PARAMETER CopyTo
+    Folder to copy the capture into and verify. Default Z:\mcl-capture.
+    Pass -CopyTo none to keep it on this PC only.
 #>
 param(
     [Parameter(Mandatory = $true)][ValidatePattern('^[A-Za-z0-9_-]{1,20}$')][string]$Label,
     [string]$Root = "C:\ProgramData\GEAerospace\MediaCreator",
-    [string]$OutDir = [Environment]::GetFolderPath("Desktop")
+    [string]$OutDir = [Environment]::GetFolderPath("Desktop"),
+    [string]$CopyTo = "Z:\mcl-capture"
 )
 $ErrorActionPreference = "Stop"
 if (-not $OutDir) { $OutDir = $PSScriptRoot }   # no Desktop (e.g. run as SYSTEM)
@@ -146,8 +156,13 @@ if ($skippedBig.Count) {
 }
 $sum | Set-Content -LiteralPath (Join-Path $dest "summary.txt") -Encoding UTF8
 
-$zip = "$dest.zip"
-Compress-Archive -Path (Join-Path $dest "*") -DestinationPath $zip -Force
+# Relative path with forward slashes, the way sha256sum -c reads it.
+function Get-RelPath($full, $base) { $full.Substring($base.Length + 1).Replace('\', '/') }
+
+$sumLines = foreach ($f in (Get-ChildItem -LiteralPath $dest -Recurse -File | Sort-Object FullName)) {
+    "$((Get-FileHash -LiteralPath $f.FullName -Algorithm SHA256).Hash.ToLower())  $(Get-RelPath $f.FullName $dest)"
+}
+[System.IO.File]::WriteAllText((Join-Path $dest "SHA256SUMS"), (($sumLines -join "`n") + "`n"))
 
 Write-Host ""
 Write-Host "Captured $($all.Count) files ($copied text files copied)." -ForegroundColor Green
@@ -157,4 +172,45 @@ if ($tags.Count -eq 0) {
 if ($unreadable.Count) {
     Write-Host "$($unreadable.Count) file(s) could not be read; listed in summary.txt." -ForegroundColor Yellow
 }
-Write-Host "Send back: $zip"
+Write-Host "Capture folder: $dest"
+
+if (-not $CopyTo -or $CopyTo -eq "none") { exit 0 }
+$drive = Split-Path -Qualifier $CopyTo -ErrorAction SilentlyContinue
+if (($drive -and -not (Test-Path -LiteralPath "$drive\")) -or -not (Test-Path -LiteralPath (Split-Path $CopyTo -Parent))) {
+    Write-Host ""
+    Write-Host "$CopyTo is not reachable, so nothing was copied." -ForegroundColor Yellow
+    Write-Host "Map Z: to the dev box pxe-images share and run again, or copy the folder above by hand."
+    exit 1
+}
+
+$target = Join-Path $CopyTo (Split-Path $dest -Leaf)
+Write-Host ""
+Write-Host "Copying to $target ..."
+& robocopy.exe $dest $target /E /COPY:DT /R:2 /W:5 /NP /NFL /NDL /NJH /NJS | Out-Null
+$rc = $LASTEXITCODE
+if ($rc -ge 8) {
+    Write-Host "Copy FAILED (robocopy exit $rc)." -ForegroundColor Red
+    exit 2
+}
+
+# Read every file back through the share and compare with SHA256SUMS.
+$bad = New-Object System.Collections.Generic.List[string]
+foreach ($line in $sumLines) {
+    $hash = $line.Substring(0, 64)
+    $rel = $line.Substring(66)
+    $copy = Join-Path $target ($rel.Replace('/', '\'))
+    if (-not (Test-Path -LiteralPath $copy -PathType Leaf)) { $bad.Add("missing  $rel"); continue }
+    $got = (Get-FileHash -LiteralPath $copy -Algorithm SHA256).Hash.ToLower()
+    if ($got -ne $hash) { $bad.Add("differs  $rel ($((Get-Item -LiteralPath $copy).Length) bytes)") }
+}
+if ((Get-FileHash -LiteralPath (Join-Path $target "SHA256SUMS") -Algorithm SHA256).Hash -ne
+    (Get-FileHash -LiteralPath (Join-Path $dest "SHA256SUMS") -Algorithm SHA256).Hash) {
+    $bad.Add("differs  SHA256SUMS")
+}
+if ($bad.Count) {
+    Write-Host "Copy NOT verified: $($bad.Count) of $($sumLines.Count + 1) files wrong." -ForegroundColor Red
+    foreach ($b in $bad) { Write-Host "  $b" }
+    exit 2
+}
+Write-Host "Copied and verified: all $($sumLines.Count + 1) files match." -ForegroundColor Green
+Write-Host "On the share: $target"