When MessageStats is first installed and MessageStats reports is first opened from the console or via the URL the landing page defaults to Corporate Exchange At A Glance.
If a user or admin changes these defaults by clicking the Configure Parts radio button and removing or adding parts/reports this can affect the Default View
To reset the view the following parts/reports need to be replaced using the Configure Parts radio button:
Click Configure Parts button
Remove all entries from the configured parts pane (Right Hand Side) using the arrows in the middle of the screen
Scroll to the bottom of the left hand side and search for Exchange Messages at a glance add using the arrows, Exchange Storage at a glance and then under the Inventory container find the Inventory Summary report.
Once added click apply and then reopen the Reports again to confirm the changes have been applied.