Session log: BirthBiologic Datto-to-SharePoint migration

Supply Management migrated (160 files), SPMT launched for 4 remaining
folders, Syncro ticket #109277420 opened, SPB license assigned to
sysadmin. Script, errors, SP site map, and next steps documented.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

clients/birth-biologic/scripts/migrate-datto-to-sharepoint.ps1

@@ -50,7 +50,8 @@ param(
     [string]$DattoRoot    = "C:\Users\Public\Desktop\Datto Workplace Server Projects",
     [string]$OnlyFolder   = "",
     [switch]$WhatIf,
-    [bool]$Resume         = $true
+    [bool]$Resume         = $true,
+    [switch]$DeltaOnly
 )
 
 $ErrorActionPreference = "Stop"
@@ -206,6 +207,10 @@ function Upload-LargeFile {
     $fileSize = (Get-Item $LocalPath).Length
     $encoded  = Encode-Path $RemotePath
 
+    # Delete any existing/partial item first so upload session creation doesn't 409
+    $deleteUri = "${GRAPH_ROOT}/sites/${SiteId}/drive/root:/${encoded}"
+    try { Invoke-Graph -Method DELETE -Uri $deleteUri | Out-Null } catch {}
+
     $sessionUri  = "${GRAPH_ROOT}/sites/${SiteId}/drive/root:/${encoded}:/createUploadSession"
     $sessionBody = '{"item":{"@microsoft.graph.conflictBehavior":"replace"}}'
     $session     = Invoke-Graph -Method POST -Uri $sessionUri -Body $sessionBody
@@ -241,6 +246,10 @@ function Upload-LargeFile {
             }
             $offset += $read
         }
+    } catch {
+        # Cancel the upload session so outer retries can start a fresh one
+        try { Invoke-RestMethod -Method DELETE -Uri $uploadUrl -ErrorAction SilentlyContinue } catch {}
+        throw
     } finally {
         $stream.Dispose()
         Write-Host ""
@@ -289,6 +298,24 @@ function Migrate-Folder {
         $sizeMB = [math]::Round($file.Length / 1MB, 2)
         Write-Log "  [$($done + $skip + $fail + 1)/$total] $relPath ($sizeMB MB)"
 
+        if ($DeltaOnly) {
+            # Check if SharePoint already has this file and it's current
+            $encoded    = Encode-Path $remotePath
+            $checkUri   = "${GRAPH_ROOT}/sites/${SiteId}/drive/root:/${encoded}?select=lastModifiedDateTime,size"
+            try {
+                $spItem    = Invoke-Graph -Method GET -Uri $checkUri
+                $spDate    = [datetime]$spItem.lastModifiedDateTime
+                $localDate = $file.LastWriteTimeUtc
+                if ($spItem.size -gt 0 -and $spDate -ge $localDate) {
+                    $skip++
+                    continue
+                }
+                Write-Log "  [DELTA] $relPath (SP: $($spDate.ToString('yyyy-MM-dd')) / Local: $($localDate.ToString('yyyy-MM-dd')))"
+            } catch {
+                # Not found in SP — upload it
+            }
+        }
+
         if ($WhatIf) {
             Write-Log "  [WHATIF] -> $remotePath"
             $done++
@@ -325,7 +352,7 @@ function Migrate-Folder {
 # Main
 Write-Log "=== BirthBiologic Datto -> SharePoint Migration ==="
 Write-Log "Source: $DattoRoot"
-Write-Log "WhatIf=$WhatIf | Resume=$Resume | OnlyFolder=$(if ($OnlyFolder) { $OnlyFolder } else { '(all)' })"
+Write-Log "WhatIf=$WhatIf | Resume=$Resume | DeltaOnly=$DeltaOnly | OnlyFolder=$(if ($OnlyFolder) { $OnlyFolder } else { '(all)' })"
 
 if (-not (Test-Path $DattoRoot)) {
     Write-Log "ERROR: Datto root not found: $DattoRoot" "ERROR"