Searching in Mimecast

In Outlook, click on the Mimecast tab in the Ribbon and then click on Search

In the Mimecast for Outlook window that opens, click on the Search Options button

Click on the Date Range dropdown and select the desired date range.

At this point you can (and probably should) include as much information as possible in the search options dialog in order to narrow down the results.

When you have finished filling in the Search Options click on Search

The results of your search will be displayed in the center panel, when you select a message it will be displayed in the preview pane on the right.

Just above the message preview there is a toolbar which will allow you to Reply, Reply All, Forward, Block the sender, Report the message as spam, Print, or Save the currently selected email.