Option Explicit
Private Sub Workbook_Open()
ActiveWorkbook.Unprotect Password:="xyz"
Dim Blatt As Worksheet
For Each Blatt In ActiveWorkbook.Worksheets
Blatt.Visible = True
Blatt.Unprotect Password:="xyz"
Blatt.Shapes("CheckBox1").Visible = Not Blatt.Range("P4") = "Wahr"
Range("B6").Select
Blatt.Protect Password:="xyz"
Next Blatt
Dim wks
For Each wks In Me.Sheets
If wks.Name <> Format(Date, "dd") Then wks.Visible = False
Next
If Format(Date - 1, "dd") <> "31" Then Sheets(Format(Date - 1, "dd")).Visible = True
If Format(Date + 1, "dd") <> "01" Then Sheets(Format(Date + 1, "dd")).Visible = True
If Range("P6") <> Range("P7") Then
Call alle_Tage
Sheets("01").Activate
End If
ActiveWorkbook.Protect Password:="xyz"
MsgBox "Willkommen zurück "
End Sub