Pop-up when database is blocked

[christophe.dewinne]

I have to do some changes in a Access-file where a lot of people have access to. Before I do that, I have to send a mail to everyone that I have to do some cleaning and that no-one may work in the file.
When someone doesn't read his mail, they can do changes that are lost afterwards.
Because of this problem, I search a way to block the database and let it know at the user by giving a pop-up when he wants to open the file. Does anyone know how to do this?

Thanks.

[RuralGuy]

It is called "Kick 'em Off" and this link has a number of ways to do it: http://www.accessmvp.com/JConrad/acc...e/kickoff.html

[christophe.dewinne]

Now I can kick the users off but they still don't know that they may not restart the program for a while.
What I search is a method to put a pop-up on screen when they try to open the database.

[RuralGuy]

I use a System table to Kick-em-off with a value in a field equal to the number of seconds before the users will shut down. I check this value when the system starts up and put up a message and quit if the value is non zero.