Option Explicit
Sub DateienLesen()
Call EventsOff
Dim DateiName As String
DateiName = Dir("C:\Temp\" & "*.xls")
Do While DateiName <> ""
If ThisWorkbook.Name <> DateiName Then
Workbooks.Open Filename:="C:\Temp\" & DateiName
Workbooks(DateiName).Worksheets(1).Range("A1:K501").Copy _
ThisWorkbook.Worksheets(1).Range("A" & ThisWorkbook.Worksheets(1).Range("A" & Rows.Count).End(xlUp).Row + 1)
Workbooks(DateiName).Close SaveChanges:=True
End If
DateiName = Dir
Loop
Call EventsOn
End Sub

Public Sub EventsOff()
With Application
.ScreenUpdating = False
.EnableEvents = False
.Calculation = xlCalculationManual
End With
End Sub

Public Sub EventsOn()
With Application
.ScreenUpdating = True
.EnableEvents = True
.Calculation = xlCalculationAutomatic
End With
End Sub