Microsoft Office Tutorials and References
In Depth Information
Understanding Offline Folders Files
Exchange stores all your information — messages, appointments, tasks, and so on — on the server.
After all, this is a main function of Exchange: to provide a central and sharable repository for
information. Does this mean you cannot work with this information when you are not connected to the
server? No, because you can use Offline Folders.
An Offline Folders File is a local copy of all your Exchange information. When you are not
connected you can work with this information, then when you reconnect the Offline Folders File is
synchronized with the Exchange server. Changes you made while working offline are copied to the
server and new information on the server, such as email messages you received while offline, are
From the perspective of the user, an Offline Folders File is exactly like a Personal Folders File
(PST). The folders display in the navigation pane in the same way, and you create, edit, and move
items in the same way. The difference is that a PST file remains local and is never synchronized
with any server.
When you set up Outlook to work with an Exchange server, the Offline Folders File is set up
automatically. It is named Outlook.ost by default and for Windows XP users is located in C:\Documents
and Settings\ username \Local Settings\Application Data\Microsoft\Outlook (the location may be
different if you are using Vista). The location of this file is rarely of any interest to the user. However,
you must attend to details of when synchronization occurs and which folders are synchronized.
By default, Outlook uses Cached Exchange Mode, explained in the next section, to keep your
offline folders synchronized with the server. Though you can turn Cached Exchange Mode off,
there is rarely any reason to do so and I do not recommend it.
Using Cached Exchange Mode
Cached Exchange Mode is the default way that Outlook synchronizes offline folders with the
server. When using this mode, Outlook always uses the local copy of your data — that is, the
offline folders — and automatically synchronizes the local copy with the Exchange server. To make
sure that Outlook is using Cached Exchange Mode:
Select Account Settings from the Tools menu to display the Account Settings dialog box.
If necessary, click the E-mail tab.
Select your Exchange account in this list (it may be the only entry in the list).
Click the Change button to display the Change E-mail Account dialog box.
Make sure that the Used Cached Exchange Mode option is selected.
If you change the setting, you will have to exit and then restart Outlook to put the new setting into