Option Explicit
Public bStop As Boolean, t As Date
Sub test()
Dim numfich As Integer
bStop = False
UserForm1.Show vbModeless
Do
t = Now
While Now - t < CDate("00:00:05")
DoEvents
Wend
numfich = FreeFile
Open "C:\tmp\test.txt" For Append As #numfich
Print #numfich, Now & vbCrLf;
Close #numfich
actualiser
Loop Until bStop
End Sub
Sub actualiser()
MsgBox "5 s d'écoulées"
End Sub