page numbering macro causes crash...

Having some trouble.  I tried fiddling with this code and at a loss.  any help would be appreciated.

Sub update()
Dim pageThis As Page
Dim Shift As Long
Dim s As Shape

    If (Shift And 1) <> 0 Then Exit Sub
    For Each pageThis In ActiveDocument.Pages
        Set sPageNumThis = pageThis.Shapes.FindShape("pagetotal")
        If Not sPageNumThis Is Nothing Then
            sPageNumThis.Text.Story = CStr(ActiveDocument.Pages.Count)
        End If
    Next pageThis
          
 
End Sub

okay, let's try this.  I'm trying to set the shift key press to stop the macro from running but it's not working.

I have this code in the 'ThisMacroStorage'

Private Sub CurDoc_PageDelete(ByVal Count As Long)
If Shift = 0 Then '(if shift is not pressed)
Dim pageThis As Page
Dim s As Shape

    For Each pageThis In ActiveDocument.Pages
        Set sPageNumThis = pageThis.Shapes.FindShape("pagetotal")
        If Not sPageNumThis Is Nothing Then
            sPageNumThis.Text.Story = CStr(ActiveDocument.Pages.Count)
        End If
    Next pageThis
End If

If Shift = 1 Then '(if shift is pressed)
End Sub
End If
End Sub

tested this version of your macro on CD2019 and no crash (shift key not used)

Thank you Mek.  The goal I have is to assign the shift key to stop the macro from running when I don't want it to.  I can re-create the crashing with a specific document with over 100 pages of images and text.  I'm not allowed to share that doc here.

this is killing me.  started drinking now.