If an application is showing a progress bar of some kind it means it is doing something. If that something is doing some work not just waiting for a network response, the app should indicator the current work it is doing.
Instead some apps use an “idiot light” approach. Case in point. My PC crashed. Startup Repair is running. All it shows is a progress indicator, not one based on completion status or time left, just a blue rectangle cycling by. Its been running for hours. Is is still doing anything, is it hung, is there hope?
Sure, for many apps, actual work status output is redundant and not useful to the “average” user. So when should more information be shown? When the elapsed time is over some threshold. Or if a user wants more information, they can signal that to the app. Many applications use this approach. Why something so fundamental as repairing disks doesn’t do this is very puzzling.
The same dialog box is used in other parts of Windows 10, like when creating a Restore Point, so we still have the same “idiot light” User Experience Design (UxD).