diff --git a/Connectors.Common/Modules/BaseModule.vb b/Connectors.Common/Modules/BaseModule.vb
index 1bc5532..c27c71a 100644
--- a/Connectors.Common/Modules/BaseModule.vb
+++ b/Connectors.Common/Modules/BaseModule.vb
@@ -29,7 +29,7 @@ Public MustInherit Class BaseModule
     Public Event OnFileProcessed As EventHandler(Of String) Implements ISync.OnFileProcessed
     Public Event OnFileError As EventHandler(Of String) Implements ISync.OnFileError
 
-    Private ReadOnly DirectoryGuid As String = Guid.NewGuid.ToString()
+    Private DirectoryGuid As String = Guid.NewGuid.ToString()
 
     Public Sub New(pLogConfig As LogConfig, pDatabase As MSSQLServer, pConfig As Config)
         MyBase.New(pLogConfig)
@@ -38,6 +38,10 @@ Public MustInherit Class BaseModule
         Config = pConfig
     End Sub
 
+    Friend Sub RefreshDirectoryGuid()
+        DirectoryGuid = Guid.NewGuid.ToString()
+    End Sub
+
     Friend Async Function FetchDocIds() As Task(Of List(Of String))
         If Config.SQLQueryFetch = "" Then
             Logger.Warn("Fetch Query is not configured. Exiting.")
diff --git a/Connectors.Common/Modules/Sharepoint/SharepointSync.vb b/Connectors.Common/Modules/Sharepoint/SharepointSync.vb
index b4c5062..20c26a5 100644
--- a/Connectors.Common/Modules/Sharepoint/SharepointSync.vb
+++ b/Connectors.Common/Modules/Sharepoint/SharepointSync.vb
@@ -20,6 +20,7 @@ Namespace Sharepoint
                 AddDivider()
 
                 EnsureOutputDirectoryExists()
+                RefreshDirectoryGuid()
 
                 Dim oExtDocIds = Await FetchDocIds()
                 If oExtDocIds Is Nothing Then
diff --git a/Connectors.Common/Modules/slt/sltSync.vb b/Connectors.Common/Modules/slt/sltSync.vb
index 51eb886..c911ea5 100644
--- a/Connectors.Common/Modules/slt/sltSync.vb
+++ b/Connectors.Common/Modules/slt/sltSync.vb
@@ -32,6 +32,7 @@ Namespace slt
                 AddDivider()
 
                 EnsureOutputDirectoryExists()
+                RefreshDirectoryGuid()
 
                 Dim oExtDocIds = Await FetchDocIds()
                 If oExtDocIds Is Nothing Then
diff --git a/Connectors.Form/frmMain.vb b/Connectors.Form/frmMain.vb
index ab276b0..b40c75b 100644
--- a/Connectors.Form/frmMain.vb
+++ b/Connectors.Form/frmMain.vb
@@ -1,5 +1,6 @@
 Imports System.ComponentModel
 Imports System.Runtime.Remoting.Messaging
+Imports System.Threading.Tasks
 Imports Connectors.Common
 Imports DevExpress.XtraEditors.ViewInfo
 Imports DigitalData.Modules.Config
@@ -15,6 +16,7 @@ Partial Public Class frmMain
 
     Private FilesProcessed As Integer = 0
     Private ErrorsOccurred As Integer = 0
+    Private SyncRunning As Boolean = False
 
     Public Enum LogLevel
         Info
@@ -48,7 +50,7 @@ Partial Public Class frmMain
             AddDivider()
 
             If ConfigManager.Config.ActiveModule = "NONE" Then
-                AddWarnEntry("No ActiveModule selected, check your configuration!", ConfigManager.Config.ActiveModule)
+                AddWarnEntry("No ActiveModule selected, check your configuration!")
                 Exit Sub
             End If
 
@@ -69,11 +71,16 @@ Partial Public Class frmMain
                 Exit Sub
             End If
 
+            If Sync.TestConfigIsComplete() Then
+                AddWarnEntry("Configuration is incomplete, check your configuration!")
+                Exit Sub
+            End If
+
             btnForceSync.Enabled = True
 
-            If ConfigManager.Config.Autostart And Sync.TestConfigIsComplete() Then
+            If ConfigManager.Config.Autostart Then
                 btnForceSync.Enabled = False
-                Await Sync.Run()
+                Await RunSync()
                 btnForceSync.Enabled = True
             End If
 
@@ -165,9 +172,26 @@ Partial Public Class frmMain
         SyncTimer.Enabled = False
     End Sub
 
+    Private Async Function RunSync() As Task
+        If SyncRunning = True Then
+            Logger.Debug("Sync still running. Skipping.")
+            Exit Function
+        End If
+
+        Try
+            SyncRunning = True
+            Await Sync.Run()
+            SyncRunning = False
+        Catch ex As Exception
+            SyncRunning = False
+            Logger.Warn("Error while running sync!")
+            Logger.Error(ex)
+        End Try
+    End Function
+
     Private Async Function Timer_Elapsed(sender As Object, e As System.EventArgs) As Threading.Tasks.Task Handles SyncTimer.Tick
         btnForceSync.Enabled = False
-        Await Sync.Run()
+        Await RunSync()
         btnForceSync.Enabled = True
     End Function
 
@@ -253,7 +277,7 @@ Partial Public Class frmMain
 
     Private Async Sub btnForceSync_ItemClick(sender As Object, e As DevExpress.XtraBars.ItemClickEventArgs) Handles btnForceSync.ItemClick
         btnForceSync.Enabled = False
-        Await Sync.Run()
+        Await RunSync()
         btnForceSync.Enabled = True
     End Sub