Hide them using a macro that uses
xlveryhidden
Then it can only be unhidden by a macro. So, hide the macros and protect
them and they will have no way of knowing they even exist. Or, put in
another file that is protected.

--
Don Guillett
Microsoft MVP Excel
SalesAid Software

"How do I protect only hidden columns?" <How do I protect only hidden
wrote in message
...
I need to hide certain columns from users that open my worksheet. I can
protect the worksheet as a read-only with password to modify but that does
not prevent another user of my document from unhiding all columns. How
can I
hide columns so that they cannot be un-hidden by other users?