Sometimes we need to undergo maintenance on the data in our custom tables or entities. These activities can range from doing a mass import of data from other sources or maybe data clean-up activities, etc.

It would be nice to be given an administrative UI mechanism that would allow System Administrators the ability to make some tables unavailable to the users temporarily and give them an "under maintenance" message when they try to access that specific table. After the System Admin has finished with his data maintenance task, he can then provide access to the users again by turning off this "under maintenance" flag.

Also, there is a precedence for this kind of mechanism. You gave us the "under maintenance" feature under Power Apps Portals. Please give us this same feature for all Dynamics 365 entities (but let us pick which entities/tables we want to disable).