Bonjour
Pour compléter la réponse de grisan29
Une autre façon
Dans un module standard
Declare Function GetWindowLongA Lib "User32" (ByVal HWnd As Long, ByVal nIndex As Long) As Long
Declare Function SetWindowLongA Lib "User32" (ByVal HWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Declare Function FindWindowA Lib "User32" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Sub SupprimerCroixFermeture(USF As UserForm)
Dim HWnd As Long
HWnd = FindWindowA("Thunder" & IIf(Application.Version Like "8*", "X", "D") & "Frame", USF.Caption)
SetWindowLongA HWnd, -16, GetWindowLongA(HWnd, -16) And &HFFF7FFFF
End Sub
Dans le module de l'userform
Private Sub UserForm_Initialize()
SupprimerCroixFermeture Me
End Sub