diff --git a/src/StarfaceOutlookSync/Services/OutlookContactsService.cs b/src/StarfaceOutlookSync/Services/OutlookContactsService.cs
index db34ecc9..da7d78eb 100644
--- a/src/StarfaceOutlookSync/Services/OutlookContactsService.cs
+++ b/src/StarfaceOutlookSync/Services/OutlookContactsService.cs
@@ -2,46 +2,62 @@ using System;
 using System.Collections.Generic;
 using System.Runtime.InteropServices;
 using StarfaceOutlookSync.Models;
-using Outlook = Microsoft.Office.Interop.Outlook;
 
 namespace StarfaceOutlookSync.Services
 {
+    /// <summary>
+    /// Zugriff auf Outlook-Kontakte per dynamic COM.
+    /// Funktioniert mit jeder Outlook Classic Version (2013-2024)
+    /// ohne Abhaengigkeit von einer bestimmten Interop-DLL.
+    /// </summary>
     public class OutlookContactsService : IDisposable
     {
-        private Outlook.Application _outlookApp;
+        private dynamic _outlookApp;
         private bool _weStartedOutlook;
 
-        // Marshal.GetActiveObject existiert nicht in .NET 8, daher P/Invoke
+        // OlDefaultFolders.olFolderContacts = 10
+        private const int OlFolderContacts = 10;
+        // OlItemType.olContactItem = 2
+        private const int OlContactItem = 2;
+
         [DllImport("oleaut32.dll", PreserveSig = false)]
-        private static extern void GetActiveObject([MarshalAs(UnmanagedType.LPStruct)] Guid rclsid, IntPtr pvReserved, [MarshalAs(UnmanagedType.IUnknown)] out object ppunk);
+        private static extern void GetActiveObject(
+            [MarshalAs(UnmanagedType.LPStruct)] Guid rclsid,
+            IntPtr pvReserved,
+            [MarshalAs(UnmanagedType.IUnknown)] out object ppunk);
 
         private static object GetActiveComObject(string progId)
         {
-            var clsid = Type.GetTypeFromProgID(progId, true).GUID;
-            GetActiveObject(clsid, IntPtr.Zero, out var obj);
+            var type = Type.GetTypeFromProgID(progId, false);
+            if (type == null) return null;
+            GetActiveObject(type.GUID, IntPtr.Zero, out var obj);
             return obj;
         }
 
-        private Outlook.Application GetOutlookApp()
+        private dynamic GetOutlookApp()
         {
             if (_outlookApp != null) return _outlookApp;
 
             // Versuch 1: Laufende Outlook-Instanz finden
             try
             {
-                _outlookApp = (Outlook.Application)GetActiveComObject("Outlook.Application");
-                _weStartedOutlook = false;
-                return _outlookApp;
+                var obj = GetActiveComObject("Outlook.Application");
+                if (obj != null)
+                {
+                    _outlookApp = obj;
+                    _weStartedOutlook = false;
+                    return _outlookApp;
+                }
             }
             catch { }
 
             // Versuch 2: Outlook per COM starten
             try
             {
-                var outlookType = Type.GetTypeFromProgID("Outlook.Application");
+                var outlookType = Type.GetTypeFromProgID("Outlook.Application", false);
                 if (outlookType != null)
                 {
-                    _outlookApp = (Outlook.Application)Activator.CreateInstance(outlookType);
+                    _outlookApp = Activator.CreateInstance(outlookType);
                     _weStartedOutlook = true;
                     return _outlookApp;
                 }
@@ -65,18 +81,21 @@ namespace StarfaceOutlookSync.Services
                 var app = GetOutlookApp();
                 var ns = app.GetNamespace("MAPI");
 
-                // Alle Stores durchgehen (jedes Konto, jede PST-Datei etc.)
-                foreach (Outlook.Store store in ns.Stores)
+                // Alle Stores durchgehen
+                var stores = ns.Stores;
+                for (int i = 1; i <= (int)stores.Count; i++)
                 {
                     try
                     {
+                        var store = stores[i];
                         var rootFolder = store.GetRootFolder();
                         FindContactFoldersRecursive(rootFolder, folders);
                         Marshal.ReleaseComObject(rootFolder);
+                        Marshal.ReleaseComObject(store);
                     }
                     catch (Exception ex)
                     {
-                        System.Diagnostics.Debug.WriteLine($"Error scanning store '{store.DisplayName}': {ex.Message}");
+                        System.Diagnostics.Debug.WriteLine($"Error scanning store {i}: {ex.Message}");
                     }
                 }
 
@@ -85,121 +104,141 @@ namespace StarfaceOutlookSync.Services
                 {
                     try
                     {
-                        var defaultFolder = ns.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderContacts);
-                        folders.Add(defaultFolder.FolderPath);
+                        var defaultFolder = ns.GetDefaultFolder(OlFolderContacts);
+                        folders.Add((string)defaultFolder.FolderPath);
                         Marshal.ReleaseComObject(defaultFolder);
                     }
                     catch { }
                 }
 
+                Marshal.ReleaseComObject(stores);
                 Marshal.ReleaseComObject(ns);
             }
             catch (Exception ex)
             {
                 System.Diagnostics.Debug.WriteLine($"Error getting folders: {ex.Message}");
+                throw;
             }
 
             return folders;
         }
 
-        private void FindContactFoldersRecursive(Outlook.MAPIFolder folder, List<string> paths)
+        private void FindContactFoldersRecursive(dynamic folder, List<string> paths)
         {
             try
             {
-                // Kontaktordner erkennen: DefaultItemType ODER Ordnername enthaelt "Kontakt"/"Contact"
-                if (folder.DefaultItemType == Outlook.OlItemType.olContactItem)
+                if ((int)folder.DefaultItemType == OlContactItem)
                 {
-                    if (!paths.Contains(folder.FolderPath))
-                        paths.Add(folder.FolderPath);
+                    string path = folder.FolderPath;
+                    if (!paths.Contains(path))
+                        paths.Add(path);
                 }
 
-                // Alle Unterordner durchsuchen
-                foreach (Outlook.MAPIFolder sub in folder.Folders)
+                var subFolders = folder.Folders;
+                for (int i = 1; i <= (int)subFolders.Count; i++)
                 {
                     try
                     {
+                        var sub = subFolders[i];
                         FindContactFoldersRecursive(sub, paths);
-                    }
-                    catch { }
-                    finally
-                    {
                         Marshal.ReleaseComObject(sub);
                     }
+                    catch { }
                 }
+                Marshal.ReleaseComObject(subFolders);
             }
             catch (Exception ex)
             {
-                System.Diagnostics.Debug.WriteLine($"Error scanning folder '{folder.Name}': {ex.Message}");
+                System.Diagnostics.Debug.WriteLine($"Error scanning folder: {ex.Message}");
             }
         }
 
-        private Outlook.MAPIFolder GetFolderByPath(string folderPath)
+        private dynamic GetFolderByPath(string folderPath)
         {
             var app = GetOutlookApp();
             var ns = app.GetNamespace("MAPI");
 
-            // Standard-Kontaktordner als Fallback
             if (string.IsNullOrEmpty(folderPath))
-                return ns.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderContacts);
+                return ns.GetDefaultFolder(OlFolderContacts);
 
             try
             {
-                // Pfad durchlaufen
                 var parts = folderPath.Split(new[] { '\\' }, StringSplitOptions.RemoveEmptyEntries);
-                Outlook.MAPIFolder current = null;
+                dynamic current = null;
 
-                foreach (Outlook.Store store in ns.Stores)
+                var stores = ns.Stores;
+                for (int i = 1; i <= (int)stores.Count; i++)
                 {
-                    if (store.GetRootFolder().Name == parts[0] ||
-                        store.GetRootFolder().FolderPath.TrimStart('\\') == parts[0])
+                    var store = stores[i];
+                    var root = store.GetRootFolder();
+                    string rootName = root.Name;
+
+                    if (rootName == parts[0])
                     {
-                        current = store.GetRootFolder();
+                        current = root;
                         break;
                     }
+                    Marshal.ReleaseComObject(root);
+                    Marshal.ReleaseComObject(store);
                 }
+                Marshal.ReleaseComObject(stores);
 
                 if (current == null)
-                    return ns.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderContacts);
+                    return ns.GetDefaultFolder(OlFolderContacts);
 
                 for (int i = 1; i < parts.Length; i++)
                 {
                     bool found = false;
-                    foreach (Outlook.MAPIFolder sub in current.Folders)
+                    var subFolders = current.Folders;
+                    for (int j = 1; j <= (int)subFolders.Count; j++)
                     {
-                        if (sub.Name == parts[i])
+                        var sub = subFolders[j];
+                        if ((string)sub.Name == parts[i])
                         {
                             current = sub;
                             found = true;
                             break;
                         }
+                        Marshal.ReleaseComObject(sub);
                     }
+                    Marshal.ReleaseComObject(subFolders);
+
                     if (!found)
-                        return ns.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderContacts);
+                        return ns.GetDefaultFolder(OlFolderContacts);
                 }
 
                 return current;
             }
             catch
             {
-                return ns.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderContacts);
+                return ns.GetDefaultFolder(OlFolderContacts);
             }
         }
 
         public List<UnifiedContact> GetContacts(string folderPath)
         {
             var contacts = new List<UnifiedContact>();
-
             try
             {
                 var folder = GetFolderByPath(folderPath);
                 var items = folder.Items;
 
-                foreach (var item in items)
+                for (int i = 1; i <= (int)items.Count; i++)
                 {
-                    if (item is Outlook.ContactItem ci)
+                    dynamic item = null;
+                    try
                     {
-                        contacts.Add(MapFromOutlook(ci));
-                        Marshal.ReleaseComObject(ci);
+                        item = items[i];
+                        // Nur ContactItems verarbeiten (Class = 40 = olContact)
+                        if ((int)item.Class == 40)
+                        {
+                            contacts.Add(MapFromOutlook(item));
+                        }
+                    }
+                    catch { }
+                    finally
+                    {
+                        if (item != null) Marshal.ReleaseComObject(item);
                     }
                 }
 
@@ -219,7 +258,8 @@ namespace StarfaceOutlookSync.Services
             try
             {
                 var folder = GetFolderByPath(folderPath);
-                var ci = (Outlook.ContactItem)folder.Items.Add(Outlook.OlItemType.olContactItem);
+                var items = folder.Items;
+                dynamic ci = items.Add(OlContactItem);
 
                 MapToOutlook(contact, ci);
                 ci.Save();
@@ -227,6 +267,7 @@ namespace StarfaceOutlookSync.Services
                 contact.OutlookEntryId = ci.EntryID;
 
                 Marshal.ReleaseComObject(ci);
+                Marshal.ReleaseComObject(items);
                 Marshal.ReleaseComObject(folder);
 
                 return contact;
@@ -244,7 +285,7 @@ namespace StarfaceOutlookSync.Services
             {
                 var app = GetOutlookApp();
                 var ns = app.GetNamespace("MAPI");
-                var ci = (Outlook.ContactItem)ns.GetItemFromID(entryId);
+                dynamic ci = ns.GetItemFromID(entryId);
 
                 MapToOutlook(contact, ci);
                 ci.Save();
@@ -267,7 +308,7 @@ namespace StarfaceOutlookSync.Services
             {
                 var app = GetOutlookApp();
                 var ns = app.GetNamespace("MAPI");
-                var ci = (Outlook.ContactItem)ns.GetItemFromID(entryId);
+                dynamic ci = ns.GetItemFromID(entryId);
 
                 ci.Delete();
                 Marshal.ReleaseComObject(ci);
@@ -282,36 +323,46 @@ namespace StarfaceOutlookSync.Services
             }
         }
 
-        private UnifiedContact MapFromOutlook(Outlook.ContactItem ci)
+        private UnifiedContact MapFromOutlook(dynamic ci)
         {
             return new UnifiedContact
             {
-                OutlookEntryId = ci.EntryID ?? "",
-                FirstName = ci.FirstName ?? "",
-                LastName = ci.LastName ?? "",
-                Company = ci.CompanyName ?? "",
-                JobTitle = ci.JobTitle ?? "",
-                Email = ci.Email1Address ?? "",
-                EmailSecondary = ci.Email2Address ?? "",
-                PhoneWork = ci.BusinessTelephoneNumber ?? "",
-                PhoneMobile = ci.MobileTelephoneNumber ?? "",
-                PhoneHome = ci.HomeTelephoneNumber ?? "",
-                Fax = ci.BusinessFaxNumber ?? "",
-                Street = ci.BusinessAddressStreet ?? "",
-                City = ci.BusinessAddressCity ?? "",
-                PostalCode = ci.BusinessAddressPostalCode ?? "",
-                State = ci.BusinessAddressState ?? "",
-                Country = ci.BusinessAddressCountry ?? "",
-                Website = ci.WebPage ?? "",
-                Notes = ci.Body ?? "",
-                Salutation = ci.Title ?? "",
-                Title = ci.Suffix ?? "",
-                Birthday = ci.Birthday != DateTime.MinValue && ci.Birthday.Year > 1900
-                    ? ci.Birthday.ToString("yyyy-MM-dd") : ""
+                OutlookEntryId = (string)(ci.EntryID ?? ""),
+                FirstName = (string)(ci.FirstName ?? ""),
+                LastName = (string)(ci.LastName ?? ""),
+                Company = (string)(ci.CompanyName ?? ""),
+                JobTitle = (string)(ci.JobTitle ?? ""),
+                Email = (string)(ci.Email1Address ?? ""),
+                EmailSecondary = (string)(ci.Email2Address ?? ""),
+                PhoneWork = (string)(ci.BusinessTelephoneNumber ?? ""),
+                PhoneMobile = (string)(ci.MobileTelephoneNumber ?? ""),
+                PhoneHome = (string)(ci.HomeTelephoneNumber ?? ""),
+                Fax = (string)(ci.BusinessFaxNumber ?? ""),
+                Street = (string)(ci.BusinessAddressStreet ?? ""),
+                City = (string)(ci.BusinessAddressCity ?? ""),
+                PostalCode = (string)(ci.BusinessAddressPostalCode ?? ""),
+                State = (string)(ci.BusinessAddressState ?? ""),
+                Country = (string)(ci.BusinessAddressCountry ?? ""),
+                Website = (string)(ci.WebPage ?? ""),
+                Notes = (string)(ci.Body ?? ""),
+                Salutation = (string)(ci.Title ?? ""),
+                Birthday = GetBirthdayString(ci)
             };
         }
 
-        private void MapToOutlook(UnifiedContact contact, Outlook.ContactItem ci)
+        private string GetBirthdayString(dynamic ci)
+        {
+            try
+            {
+                DateTime bday = ci.Birthday;
+                if (bday.Year > 1900 && bday != DateTime.MinValue)
+                    return bday.ToString("yyyy-MM-dd");
+            }
+            catch { }
+            return "";
+        }
+
+        private void MapToOutlook(UnifiedContact contact, dynamic ci)
         {
             ci.FirstName = contact.FirstName;
             ci.LastName = contact.LastName;
@@ -348,7 +399,7 @@ namespace StarfaceOutlookSync.Services
                 {
                     try { _outlookApp.Quit(); } catch { }
                 }
-                Marshal.ReleaseComObject(_outlookApp);
+                try { Marshal.ReleaseComObject(_outlookApp); } catch { }
                 _outlookApp = null;
             }
         }
diff --git a/src/StarfaceOutlookSync/StarfaceOutlookSync.csproj b/src/StarfaceOutlookSync/StarfaceOutlookSync.csproj
index acce1f2d..7cf75307 100644
--- a/src/StarfaceOutlookSync/StarfaceOutlookSync.csproj
+++ b/src/StarfaceOutlookSync/StarfaceOutlookSync.csproj
@@ -19,7 +19,6 @@
 
   <ItemGroup>
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
-    <PackageReference Include="Microsoft.Office.Interop.Outlook" Version="15.0.4797.1004" />
   </ItemGroup>
 
 </Project>