Cached Exchange Mode can provide you with a better experience when you use Outlook. A copy of your mailbox and GAL (global address book) is "cached" on your computer. This copy provides quick access to your data and is frequently updated with the mail server. Note: the time required to complete the initial synchronization will depend on the size of your mailbox. Access to all data is not available until the initial synchronization is complete.

Cached Exchange Mode is the premier configuration in Outlook.  Most users will find that Cached Exchange Mode performs faster than online mode.   Use of Cached Exchange Mode shields the user from network and server connection issues and facilitates switching from online to offline for mobile users.

Also, quite a number of features in Outlook require Cached Exchange Mode in order for them to work or to work better. The most notable features are:

  • Work Offline
  • Junk E-mail Filter
  • Instant Search
  • Conversation View (Show Messages from Other Folders)
  • Clean Up
  • People Pane / Outlook Social Connector

This means that when you are using an Exchange account, you will need to enable Cached Exchange Mode (CEM) for them to work.

Enabling Cached Exchange Mode

Cached Exchange Mode is enabled by default when you configure an Exchange account and is also highly recommended. If you have Cached Exchange Mode disabled for some reason, you can enable it by following the steps below:

  1. Choose File-> Info-> Account Settings-> Account Settings…
  2. Double click your Exchange account and select the option: Use Cached Exchange Mode. The default setting is 12 months.
  3. Click Next.
  4. Click Finish.

Note: you will need to quit and restart Microsoft Outlook for this change to take effect.

To disable Cached Exchange Mode, repeat the steps but uncheck "Use Cached Exchange Mode".


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Last updated: 
May 19, 2016