Hi Andress,
Here is some code that you can put in the ThisWorkbook event module to expand all the filters on the active worksheet before saving. If you want to target a specific worksheet other than the active worksheet just replace ActiveSheet with Worksheets("Your worksheet name") in the code below.
Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
'Expand (turn off) all filters on the active worksheet
Dim Fltr As Filter
Dim iFiltr As Integer
With ActiveSheet.AutoFilter
For iFiltr = 1 To .Filters.Count
If .Filters(iFiltr).On Then
.Range.AutoFilter field:=iFiltr
End If
Next iFiltr
End With
End Sub
To install this code simply right-click on the Excel icon at the left end of the Excel Worksheet Menu Bar, select View Code, and paste the above code into the VBE code pane.