Well, you could do this by having a formula that compares TODAY() with
some fixed date to see if it exceeds 10 days, but what is the point?
You can easily just highlight the cells and see the values that are in
there.

One approach you might take is to hide the sheets with a macro
(xlveryhidden) and to have just one sheet visible that says "Enable
macros in order to use this workbook" and then have a macro in another
workbook which just loads your file and hides/unhides the relevant
sheets. Tell your user to start with the "loader" file. The loader
file can create a text file somewhere containing the date it is first
used, so this can be compared with TODAY to determine if the other
file should be opened or not.

Hope this helps.

Pete

On Jul 24, 1:31 pm, wx4usa wrote:
On Jul 23, 5:15 pm, wx4usa wrote:

I've built an excel workbook and I have someone that would like to
look at it. Can I provide them a copy with a macro of some kind that
would require a password to open at 10 days or a period I specify? Can
it include a message that the trial period is over?

Is that possible? I know that passwords can be cracked, but I don't
think there is much of a threat from my potential clients.

Is there a way to conditionally format the pertinent cells (10 cells
+/-) on a page to fill black and become useless after a 10 day
period?