diff --git a/playbook/shopfloor-setup/Standard/Restore-UDCData.ps1 b/playbook/shopfloor-setup/Standard/Restore-UDCData.ps1
index ace258e..30650e2 100644
--- a/playbook/shopfloor-setup/Standard/Restore-UDCData.ps1
+++ b/playbook/shopfloor-setup/Standard/Restore-UDCData.ps1
@@ -163,11 +163,17 @@ Log "  CurrentData.json src: $(if ($srcCurExists) { 'present' } else { 'absent'
 $srcArcExists = Test-Path -LiteralPath $srcArc
 Log "  ArchivedData/ src:    $(if ($srcArcExists) { 'present' } else { 'absent' }) - $srcArc"
 
-if (-not $srcCurExists) {
-    Log "No backup waiting for bay $mn - no work to do this cycle."
+if (-not $srcCurExists -and -not $srcArcExists) {
+    Log "No backup waiting for bay $mn (neither CurrentData.json nor ArchivedData\ at bay root) - no work to do this cycle."
     Log 'Exit 0.'
     exit 0
 }
+if (-not $srcCurExists) {
+    Log "Partial backup waiting (ArchivedData\ present, CurrentData.json absent). Will restore ArchivedData\ only. Source PC may have had no live UDC session at backup time, or backup partially failed." 'WARN'
+}
+if (-not $srcArcExists) {
+    Log "Partial backup waiting (CurrentData.json present, ArchivedData\ absent). Will restore CurrentData.json only." 'WARN'
+}
 
 # -- We have a backup. Restore. ------------------------------------------
 Log "Backup waiting at $bayDir - proceeding with restore"
@@ -203,19 +209,23 @@ if (-not (Test-Path -LiteralPath $UdcDataDir)) {
 $localCur = Join-Path $UdcDataDir 'CurrentData.json'
 $localArc = Join-Path $UdcDataDir 'ArchivedData'
 
-# Copy CurrentData.json
+# Copy CurrentData.json (only if present at source)
 $copiedCur = $false
-Log "Copying CurrentData.json"
-Log "  src: $srcCur"
-Log "  dst: $localCur"
-try {
-    Copy-Item -LiteralPath $srcCur -Destination $localCur -Force -ErrorAction Stop
-    $copiedCur = $true
-    $sz = (Get-Item -LiteralPath $localCur).Length
-    Log "  OK ($sz bytes)"
-} catch {
-    Log "  FAILED" 'ERROR'
-    LogErr $_
+if ($srcCurExists) {
+    Log "Copying CurrentData.json"
+    Log "  src: $srcCur"
+    Log "  dst: $localCur"
+    try {
+        Copy-Item -LiteralPath $srcCur -Destination $localCur -Force -ErrorAction Stop
+        $copiedCur = $true
+        $sz = (Get-Item -LiteralPath $localCur).Length
+        Log "  OK ($sz bytes)"
+    } catch {
+        Log "  FAILED" 'ERROR'
+        LogErr $_
+    }
+} else {
+    Log "CurrentData.json not present in backup - skipping that copy step"
 }
 
 # Copy ArchivedData/
@@ -245,9 +255,14 @@ if ($srcArcExists) {
     Log "ArchivedData/ not present in backup - skipping that copy step"
 }
 
-# One-shot consumption: only move backup -> migrated/ if everything required succeeded
-$consumeOk = ($copiedCur -and ($copiedArc -or -not $srcArcExists))
-Log "consumeOk=$consumeOk (copiedCur=$copiedCur, copiedArc=$copiedArc, srcArcExists=$srcArcExists)"
+# One-shot consumption: only consume when every present source has been
+# successfully copied. If a source was absent we don't fault on it; if a
+# source was present but copy failed, we leave the live backup for retry.
+# Must have copied at least one thing to consume.
+$consumeOk = (($copiedCur -or -not $srcCurExists) -and `
+              ($copiedArc -or -not $srcArcExists) -and `
+              ($copiedCur -or $copiedArc))
+Log "consumeOk=$consumeOk (copiedCur=$copiedCur, copiedArc=$copiedArc, srcCurExists=$srcCurExists, srcArcExists=$srcArcExists)"
 
 if ($consumeOk) {
     try {
@@ -258,8 +273,10 @@ if ($consumeOk) {
         if (-not (Test-Path -LiteralPath $migDir))   { New-Item -ItemType Directory -Path $migDir   -Force | Out-Null }
         if (-not (Test-Path -LiteralPath $migStamp)) { New-Item -ItemType Directory -Path $migStamp -Force | Out-Null }
 
-        Move-Item -LiteralPath $srcCur -Destination (Join-Path $migStamp 'CurrentData.json') -Force -ErrorAction Stop
-        Log "  moved CurrentData.json"
+        if (Test-Path -LiteralPath $srcCur) {
+            Move-Item -LiteralPath $srcCur -Destination (Join-Path $migStamp 'CurrentData.json') -Force -ErrorAction Stop
+            Log "  moved CurrentData.json"
+        }
         if (Test-Path -LiteralPath $srcArc) {
             Move-Item -LiteralPath $srcArc -Destination (Join-Path $migStamp 'ArchivedData') -Force -ErrorAction Stop
             Log "  moved ArchivedData/"
@@ -275,7 +292,9 @@ if ($consumeOk) {
             DestinationHostname = $env:COMPUTERNAME
             DestinationUser     = $whoami
             MachineNumber       = $mn
-            CurrentDataBytes    = (Get-Item -LiteralPath $localCur).Length
+            CurrentDataPresent  = $copiedCur
+            CurrentDataBytes    = if ($copiedCur) { (Get-Item -LiteralPath $localCur).Length } else { 0 }
+            ArchivedDataPresent = $copiedArc
             ArchivedDataFiles   = $arcFiles
             ArchivedDataBytes   = $arcBytes
             RestoredVia         = 'Restore-UDCData.ps1 (manifest engine, on logon)'
@@ -295,7 +314,7 @@ if ($consumeOk) {
 # Relaunch UDC with the current machine number args. UDC's vendor autostart in
 # HKLM\Run will also fire on the next user logon, so this is belt-and-suspenders
 # for the same-session case (e.g. tech is at the keyboard during the restore).
-if ((Test-Path -LiteralPath $UdcExePath) -and $copiedCur) {
+if ((Test-Path -LiteralPath $UdcExePath) -and ($copiedCur -or $copiedArc)) {
     Log "Relaunching UDC.exe: `"$Site`" -$mn"
     try {
         Start-Process -FilePath $UdcExePath -ArgumentList @("`"$Site`"", "-$mn")