Chris,

You can add a sheet and then make it "Very Hidden" with the use of VBA.
Each time the workbook is opened, you can increase a counter, or check the
atomic date/time via the web and compare it against variables stored on this
"Very Hidden" sheet.

http://www.ingenio.com/categories/ca...sp?sid=5228306

"Chris" wrote:

I have a workbook that I send out to third parties, I want to limit its use
either by time or number of times opened- is this possible? I want to guard
against out of date data being in circulation.