Hidden the root site from client Office application.
If a user signs in with an Office 365 account in a client Office application, it will display [site - tenant name] on [save as] or [open] page.
In order to prevent the user from accessing the root site from the client, I want to set [site - tenant name] not to be displayed.
Matt Mueller commented
This or be able to toggle it on/off for customers that have not migrated to their SPO Tenant yet can remove it as an options to not confuse end users.