Dynamics CRM Online came up with Sandbox functionality (ref: https://technet.microsoft.com/en-us/library/dn659833.aspx) that provides separate instance for development/testing purpose. Sandbox instance comes up with “Admin mode” functionality that allows the admin to turn on/off.

Admin mode allows users with System Administrator or System Customizer security privilege to access the CRM system, while the rest will receive a notification, similar to:

It is a common requirement for production deployment, during this period that normal users should not access the production environment to prevent data loss and interruption when the changes/deployment is in place. Now, as the “Admin mode” functionality only available for Sandbox instance at this moment, the option that we can do to achieve this is to switching Production instance to Sandbox instance temporarily, enable the Admin mode, put some friendly maintenance warning and that’s it, your normal user won’t be able to access the instance until the Admin mode has been disabled. Don’t forget to turn the instance back to Production.

This functionality is also useful to prevent normal users to access development environment and get lost in it 🙂

HTH!