Trying to loop through all Excel files

ShazSh 

Try this - please test it on a copy of your folder first.

It will handle font name, font style, font color and fill color, but not fill effects, borders or number formatting. The code could be expanded for those.

Sub Folder()
    Dim strFolder As String
    Dim strFile As String
    Dim wbk As Workbook
    Dim wsh As Worksheet
    Dim I As Long
    Dim xRg As Range
 
    With Application.FileDialog(4)
        If .Show Then
            strFolder = .SelectedItems(1)
        Else
            MsgBox "You haven't selected a folder!", vbExclamation
            Exit Sub
        End If
    End With

    If Right(strFolder, 1) <> "\" Then
        strFolder = strFolder & "\"
    End If

    Application.ScreenUpdating = False
    strFile = Dir(strFolder & "*.xls*")
    Do While strFile <> ""
        Set wbk = Workbooks.Open(strFolder & strFile)
        For Each wsh In wbk.Worksheets
            For Each xRg In wsh.UsedRange
                If xRg.FormatConditions.Count Then
                    xRg.Font.Name = xRg.DisplayFormat.Font.Name
                    xRg.Font.FontStyle = xRg.DisplayFormat.Font.FontStyle
                    xRg.Font.Color = xRg.DisplayFormat.Font.Color
                    If xRg.DisplayFormat.Interior.ColorIndex = xlColorIndexNone Then
                        xRg.Interior.ColorIndex = xlColorIndexNone
                    Else
                        xRg.Interior.Color = xRg.DisplayFormat.Interior.Color
                    End If
                End If
            Next xRg
            wsh.UsedRange.FormatConditions.Delete
        Next wsh
        strFile = Dir
    Loop
    Application.ScreenUpdating = True
End Sub