Unfortunately, all the user has to do to defeat this method is to
save the workbook once it's open, and decline to save it when it's
closed. The worksheet will be unhidden the next time the file is
opened, even if macros are disabled. The routine could be more
sophisticated by using a Before_Save event macro to hide the
sheet(s) again, save, then unhide them, but that's not too hard to
bypass either.

Note that xlVeryHidden doesn't really hide the worksheet very well -
xlVeryHidden worksheets are still listed in the Contents pane of the
Properties dialog.

And it doesn't really address the issue of the OP - simply setting
the system clock back will allow entries after the expiration date.
Any sufficiently motivated person of average intelligence,
especially if they have access to these groups, can bypass any
protection scheme that XL has - it's just not a secure platform.


In article , (mk)
wrote:

There is a way to force user to enable macros.

Sub auto_close()
Sheets("Sheet1").Visible=xlVeryHidden
End Sub

Sub auto_open()
Sheets("Sheet1").Visible=True
End Sub