Solution immédiate "à la con"
Pour faire mieux, il faudrait un extrait de tes fichiers texte avec des dates avant le 12 du mois
Sub DOUBLON()
'
' DOUBLON Macro
'
'
Cells.Select
Application.CutCopyMode = False
derL = Range("J" & Rows.Count).End(xlUp).Row
For i = 2 To derL
If Val(Left(Cells(i, "A"), 2)) <= 12 Then
Cells(i, "L") = DateValue(Mid(Cells(i, "A"), 4, 2) & "/" & Mid(Cells(i, "A"), 1, 2) & "/" & Mid(Cells(i, "A"), 7, 13))
Else
Cells(i, "L") = DateValue(Cells(i, "A"))
End If
Next
ActiveWorkbook.Worksheets("RECAP").Sort.SortFields.Clear
ActiveWorkbook.Worksheets("RECAP").Sort.SortFields.Add Key:=Range("L2:L" & derL), _
SortOn:=xlSortOnValues, Order:=xlDescending, DataOption:=xlSortNormal
With ActiveWorkbook.Worksheets("RECAP").Sort
.SetRange Range("A1:L" & derL)
.Header = xlYes
.MatchCase = False
.Orientation = xlTopToBottom
.SortMethod = xlPinYin
.Apply
End With
ActiveSheet.Range("$A$1:$L$" & derL).RemoveDuplicates Columns:=7, Header:=xlNo
Range("A1").Select
Sheets("accueil").Select
MsgBox "Import Terminer"
'Call MASQUER
End Sub