Outlook for Mac 2011 automatically checks for new email by polling the Exchange Server for changes by using an Exchange Web Services (EWS) GetEvents
call. Versions of Outlook for Mac 2011 that are earlier than version 14.2 poll the server every one minute. Version 14.2 and later versions poll the server every 30 seconds. You cannot modify this automatic time interval.
In addition to the automatic process, you can manually synchronize some or all folders in your mailbox.Manually synchronize a specific folder
In the Navigation Pane, right-click the folder, and then select Synchronize now.Manually synchronize all folders
In the Mail module, click the Home tab, and then click Send/Receive.