Compile error: Method or data member not found error [Only on Mac; OK on Windows]

Hi,

I have the following code that works perfectly on a Windows machine, but generates that compile error on a Mac.

The piece of code that blows up is ".Unprotect" in this simple loop:

    For Each ws In ThisWorkbook.Worksheets
        ws.Unprotect Password:=pWord
    Next ws

The entire macro where that code snippet lies is:

Sub Protection_Off()

    Dim pWord As String
    Dim ws As Worksheet
    
    pWord = InputBox("Please enter the password", "Model Protection")
    
    If pWord = "" Or StrPtr(pWord) = 0 Then
    Sheet2.OLEObjects("opt_AdministrationSheets_Hide").Object.Value = True
    Exit Sub
    End If
    
    On Error GoTo ErrorTrap1
    
    Application.ScreenUpdating = False

'   Workbook protection
    ActiveWorkbook.Unprotect Password:=pWord
    
'   Worksheet protection
    For Each ws In ThisWorkbook.Worksheets
        ws.Unprotect Password:=pWord
    Next ws
    
    For Each ws In ThisWorkbook.Worksheets
        ws.Visible = xlSheetVisible
    Next ws
       
    NamedRanges_Show
    TableOfContents_ShowAdminRows

'   Make the ToC tab the active window
    Application.Goto reference:=Sheet2.Range("A1"), Scroll:=True
    
    MsgBox "Protection disabled.", vbExclamation, "Model Protection"
    
    Application.ScreenUpdating = True
    
    Exit Sub
    
ErrorTrap1:
    Sheet2.OLEObjects("opt_AdministrationSheets_Hide").Object.Value = True
    Application.ScreenUpdating = True
    MsgBox "Password incorrect - protection still enabled.", vbExclamation, "Model Protection"
    Exit Sub
    
End Sub

Thanks for any guidance on this!

Lawrence