diff --git a/Services.ZUGFeRDService/ThreadRunner.vb b/Services.ZUGFeRDService/ThreadRunner.vb
index b4d3f49f..fa932f9f 100644
--- a/Services.ZUGFeRDService/ThreadRunner.vb
+++ b/Services.ZUGFeRDService/ThreadRunner.vb
@@ -21,6 +21,9 @@ Public Class ThreadRunner
     Private ReadOnly _jobArguments As WorkerArgs
     Private ReadOnly _mssql As MSSQLServer
 
+    Private ReadOnly RejectedMaxDifferenceInMinutes As Integer = 60
+    Private RejectedLastRun As Date = Now.AddMinutes(-(RejectedMaxDifferenceInMinutes - 1))
+
     Public Sub New(LogConfig As LogConfig, ConfigManager As ConfigManager(Of Config), Firebird As Firebird, Optional MSSQL As MSSQLServer = Nothing)
         _logConfig = LogConfig
         _logger = _logConfig.GetLogger()
@@ -137,26 +140,47 @@ Public Class ThreadRunner
         End If
     End Sub
 
+    Private Sub MaybeUpdateRejected()
+        Try
+            Dim oTimeUnit = "HOUR"
+            Dim oTimeValue = 12
+
+            Dim oDifference As TimeSpan = Now - RejectedLastRun
+            If oDifference.TotalMinutes < RejectedMaxDifferenceInMinutes Then
+                Exit Sub
+            End If
+
+            _logger.Info("Updating rejected files in Firebird.")
+
+            Dim oSQL = $"
+                SELECT [EMAIL_MSGID] 
+                FROM TBEMLP_HISTORY 
+                WHERE (STATUS = 'REJECTED' OR CUST_REJECTED = 1) 
+                AND DATEDIFF({oTimeUnit}, CHANGED_WHEN, GETDATE()) <= {oTimeValue} 
+                ORDER BY GUID DESC"
+            Dim oDT As DataTable = _mssql.GetDatatable(oSQL)
+            If Not IsNothing(oDT) Then
+                For Each oROW As DataRow In oDT.Rows
+                    Dim oUpdate = $"UPDATE TBEDM_ZUGFERD_HISTORY_IN SET REJECTED = True WHERE MESSAGE_ID = '{oROW.Item(0)}' and REJECTED = false"
+                    _firebird.ExecuteNonQuery(oUpdate)
+                Next
+            End If
+        Catch ex As Exception
+            _logger.Warn("Error while Updating REJECTED State: " & ex.Message)
+        Finally
+            RejectedLastRun = Now
+        End Try
+    End Sub
+
     Private Sub DoWork(sender As Object, e As DoWorkEventArgs) Handles _workerThread.DoWork
         Try
-            Try
-                Dim oSQL = "SELECT [EMAIL_MSGID] FROM TBEMLP_HISTORY WHERE (STATUS = 'REJECTED' OR CUST_REJECTED = 1) and DATEDIFF(DAY,CHANGED_WHEN,GETDATE()) <= 2 order by guid desc"
-                Dim oDT As DataTable = _mssql.GetDatatable(oSQL)
-                If Not IsNothing(oDT) Then
-                    For Each oROW As DataRow In oDT.Rows
-                        Dim oUpdate = $"UPDATE TBEDM_ZUGFERD_HISTORY_IN SET REJECTED = True WHERE MESSAGE_ID = '{oROW.Item(0)}' and REJECTED = false"
-                        _firebird.ExecuteNonQuery(oUpdate)
-                    Next
-                End If
-            Catch ex As Exception
-                _logger.Warn("Error while Updating REJECTED State: " & ex.Message)
-            End Try
+            MaybeUpdateRejected()
 
-            Dim args As WorkerArgs = e.Argument
+            Dim oArgs As WorkerArgs = e.Argument
             _logger.Debug("Background worker running..")
 
-            Dim job As New ImportZUGFeRDFiles(_logConfig, _firebird, _config.Config.MSSQLEmailOutAccountID, _config.Config.PORTAL_NAME, _mssql)
-            job.Start(args)
+            Dim oJob As New ImportZUGFeRDFiles(_logConfig, _firebird, _config.Config.MSSQLEmailOutAccountID, _config.Config.PORTAL_NAME, _mssql)
+            oJob.Start(oArgs)
         Catch ex As Exception
             _logger.Warn("Background worker failed!")
             _logger.Error(ex)