Astuce qui m'a servit aujourd'hui au boulot, je sauve ici si jamais j'en ai besoin de nouveau :
Close the workbook and open the workbook file in the hex editor. Find
the string "DPB" and change it to "DPx" (x is in small letter). Save
the file. Open the workbook and click OK until the workbook is open
(one or more dialogs are displayed describing various problems with
the VBA project). Press ALT+F11, choose the menu command Tools-
>VBAProject Properties, navigate to the Protection tab, and change the
password but do not remove it (note the new password). Save, close,
and re-open the workbook. Press ALT+F11 and enter the new password.
Choose Tools->VBAProject Properties, navigate to the Protection tab,
and remove the password. Save the workbook.
Now open the same workbook, You can use the password that you already
given.