How to Make a Tool 'EXPIRE' After a certain date

[Mike]

Hey EXCEL community:

Here's a challenge -> I am creating a tool on Excel that
I am going to send out to a large number of people. I
want the tool to 'EXPIRE' after a certain time (like 3
months). I have used the =IF(TODAY()>"A CERTAIN
DATE","EXPIRE",CALCULATION). However, if you set the
system clock back to the past, it will work again.

Any ideas how to make the tool not work after a certain
date? IE, link the time reference to an outside source,
etc.?

Regards,

Mike

 

[BrianB]

It would be possible to change the code with code on the first occasio
the date is exceeded - even if you just add "End"