Hallo Holger,

Ok dann werde ich mal mehr posten. Das ganze ist einem Formular hinterlegt, welches eine Eingabemaske für Username und Passwort darstellt.

Private Sub cmd_login_Click()
Dim pruefung As Boolean
Dim einblenden As Boolean
Dim s As Integer
Dim z As Integer
Dim Benutzer As String


pruefung = True
einblenden = False

    If loginname = "" And txtPasswort = "" Then
        MsgBox ("Please insert Product group and Password!")
        loginname.SetFocus
        Exit Sub
    End If

    If loginname = "" Then
        MsgBox ("Please insert Product group!")
        txtPasswort = ""
        loginname.SetFocus
        
        Exit Sub
     
    End If

 
    If txtPasswort = "" Then
        MsgBox ("Please enter Password!")
        txtPasswort.SetFocus
        Exit Sub
    End If
    
  
    s = 2
    Do While Worksheets("master").Cells(1, s) <> ""
        If loginname = Worksheets("master").Cells(1, s) And _
        txtPasswort <> Worksheets("master").Cells(2, s) Then
            MsgBox ("Password invalid!")
            txtPasswort = ""
            txtPasswort.SetFocus
            pruefung = False
        ElseIf loginname = Worksheets("master").Cells(1, s) And _
        txtPasswort = Worksheets("master").Cells(2, s) Then
            pruefung = False
            einblenden = True
            Benutzer = loginname
            Unload Me
            var.productlogin = loginname
            Start.Show
        End If
        s = s + 1
    Loop
    
      If pruefung = True Then
        MsgBox ("No valid Product group!")
        loginname = ""
        txtPasswort = ""
        loginname.SetFocus
        Exit Sub
    End If
    
    If einblenden = True Then
        'show sheets
        s = 2
        z = 3
        Do Until Worksheets("master").Cells(1, s) = loginname
           s = s + 1
        Loop
        Dim Tabellenblatt As String
        Tabellenblatt = Worksheets("master").Cells(z, s)
        Do Until Worksheets("master").Cells(z, s) = ""
            Sheets(Tabellenblatt).Visible = xlSheetVisible
            z = z + 1
            Tabellenblatt = Worksheets("master").Cells(z, s)
        Loop
        Worksheets("Login").Visible = xlSheetVeryHidden
 
    End If
    
  

Vielen Dank schonmal!

LG