When you’re managing a multi-user Microsoft Access application, there are times when you need all users out of the database so that you can make changes to table structures and other items. Asking everyone to shut down is unreliable and using the Windows Task Manager to forcibly shut down instances of Microsoft Access is risky at best. Most multi-user apps should be split into separate front-end / back-end files with each user having a separate copy of the front-end so you need something that will signal all those copies to shut down and stay shut down until whatever maintenance you’re performing is complete.
In summary, my preferred way to do this is to use a settings table in the back-end database file that includes a boolean field which can be set to True to activate maintenance mode. The front-end files contain a form that stays open but hidden in the background as long as the application is open. This form uses a timer to check the value of the boolean field every 10 minutes or so. If the field is set to True, the application will notify the user, give them a minute or two to finish what they’re doing and then use the Applicaiton.Quit command to shut down automatically.
Ideally, you should still communicate with the users to let them know the database will be down for a period of time but this method helps with users who leave the app open overnight or while out to lunch, etc..

Do you need help with Microsoft Access?
Comeau Software Solutions specializes in the development and enhancement of Microsoft Access applications. We can also rescue Access projects that have gone off-track and help you decide when it's time to move to another solution. Please contact us for more information on how we can help you with your database needs.
Also, check out our online course Managing Your Data with Microsoft Access. You can learn how to build and manage your own applications and work with your data more efficiently!