When you’re hunting an attachment, Instant Search can show you only those email messages that include attachments.
In the folder pane, click a folder.
When you click Inbox, all folders in that email account are included in the search. For other folders, the default is to search only the selected folder. Don’t worry. You can change this in the next step.
At the top of the message list, click in the Instant Search box or press Ctrl+E.
No matter which folder you clicked, you can choose which folders are searched. In the Instant Search box, click the down arrow for scope options
Click Search > Has Attachments.
If the message you expected isn’t found, try expanding the search to All Mailboxes or All Outlook Items.
Clear search results
In the Instant Search box, click or click Search > Close Search.
Also, when you click a different folder in the Folder Pane, the message list returns to the default view.