With a Microsoft Exchange Server or Office 365 account, you can work disconnected to dodge association charges or prevent Outlook from endeavoring to send and get messages over a moderate system association.
How to Use Offline Folders with your Exchange Account?
On the File menu, click Work Offline.
Select or clear the Prompt me at startup so I may choose to work offline or online check box, and then click OK.
Click Yes to copy the data from the server to your new Offline Folder file (.ost).
Choose the folders that you want to be available for offline use.
Get Office 365 setup & support here : office.com/setup
How to Use Cached Exchange Mode?
On the Tools menu, click Account Settings.
Select your Exchange account, and then click Change.
Under Microsoft Exchange, select the Use Cached Exchange Mode check box.
Exit and then restart Outlook.
How to Change the Folders and Content that are Available Offline?
On the Tools menu, point to Send/Receive, point to Send/Receive Settings, and then click Define Send/Receive Groups.
In the list, click the Send/Receive group that contains your Exchange account, and then click Edit.
Under Accounts, select your Exchange account.
Under Folder Options, select the check box for each folder that you want to use offline.
for more details, visit : www.office.com/setup