When you search, the search results appear in the main Outlook window. They will remain there until you tell Outlook what to do next — say, perform another search or return to your Inbox.
You'll always know that you're looking at search results if the Instant Search pane is active. You can tell if the pane is active if it's a different color from the surrounding panes and you see the words (Search Results) after the folder name at the top of the pane.
To restore all of the messages in the current folder, click the Clear Search button.
Tip You also can clear a search by clicking a folder in the Navigation Pane (for example, click Inbox in the Navigation Pane to restore the view in which you can see all of the messages in your Inbox).