By default, Hard Disk Sentinel detects and displays all drives currently connected to the actual system. Hard Disk Sentinel saves the status, changes, logs, statistics about these drives, so can provide details about the history of them.
When a disk drive removed, no longer accessible, disconnected, the previously saved status information still present and by using the Open status of offline disks function, we can re-load the last known status and examine possible changes, degradations, logs, statistics - just like if the drive would be still connected and actively monitored.
In this window, it is possible to select any disk drive(s) to be read this way. Then the drive appears with dark blue color in the upper left area (the list of physical drives) in the main window, indicating that it is not actively monitored, no longer connected (offline) but can be used to review its state and history.