Der Code im Initialize - Ereignis des Userforms.
Private Sub UserForm_Initialize()
Dim objDic As Object
Dim lngZ As Long
Set objDic = CreateObject("Scripting.Dictionary")
For lngZ = 2 To Cells(Rows.Count, 1).End(xlUp).Row
objDic(Cells(lngZ, 1).Value) = 0
Next
Me.ComboBox1.List = objDic.keys
End Sub