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Configure Cached Exchange Mode in Outlook 2013

  • Article

 

Applies to: Office 365 ProPlus, Outlook 2013

Summary: Configure Outlook 2013 for Cached Exchange Mode so users can access their recent Exchange server email messages offline.

Audience: IT Professionals

Business doesn’t stop when workers are on the road. Cached Exchange Mode gives your enterprise users access to their recent email messages (by default 12 months’ worth, but it can be more or less) when they are on the go and disconnected from the Exchange Server. They can read and respond to their cached messages while offline and any new messages or responses they composed while offline are automatically sent when they are reconnected.

Are you a user?

If you’re not an administrator, this article is not for you. But we can point you in the right direction if you want to learn how to turn on Cached Exchange Mode in Outlook 2013 or change how much email to keep offline.

Are you an admin?

If you’re an administrator, this article tells you how to configure organization-wide Outlook Cached Exchange Mode settings for Outlook 2013.

In this article:

  • Overview

  • Before you begin

  • Configure Cached Exchange Mode

    • To configure Cached Exchange Mode settings by using the OCT

    • To configure Cached Exchange Mode settings by using Group Policy

    • To configure a default .ost location by using Group Policy

    • To prevent a new .ost file from being created

Overview

When an Outlook 2013 account is configured to use Cached Exchange Mode, there’s always a local copy of a user’s Exchange mailbox ready in an offline data file (.ost file) on the user’s computer (by default in the C:\Users\<username>\AppData\Local\Microsoft\Outlook folder.)

Offline computer with OAB and .ost folder.

Whenever the user is offline and using Outlook 2013, the program works from this local copy and with the Offline Address Book (OAB). When the user is online, the cached mailbox and OAB are periodically updated from the Exchange Server computer in the background. Any email messages the user drafted while offline are automatically sent when that user is back online.

Important

Outlook 2013 Cached Exchange Mode works only with Exchange Server 2007 or later email accounts.

If a user upgrades from an earlier version of Outlook to Outlook 2013 and you previously configured Outlook for Cached Exchange Mode, those old Cached Exchange Mode settings are automatically applied to Outlook 2013. For example, if a user account was configured to use Cached Exchange Mode in Office Outlook 2003, Office Outlook 2007, or Outlook 2010, Cached Exchange Mode remains enabled when the user upgrades to Outlook 2013. The default location for new .ost or OAB files is: %userprofile%\AppData\Local\Microsoft\Outlook\Offline Address Books. As an administrator, you can configure a different .ost file location for users in your organization who do not already have .ost files. If you do not specify a different .ost file location, Outlook creates an .ost file in the default location when users start Outlook in Cached Exchange Mode.

By default, when Outlook 2013 is installed, a new compressed version of the .ost file is created. This compressed.ost file is up to 40 percent smaller than the ones created by earlier versions of Outlook. We recommend using the new, compressed .ost file, but if you feel you must keep using to the old uncompressed .ost files, use the Outlook Group Policy template and enable the Do not create new OST file on upgrade policy.

Sync Slider (the Mail to keep offline slider in the Outlook 2013 Server Settings dialog box) and Exchange Fast Access are two new features that are available by default with Cached Exchange Mode in Outlook 2013.

The Outlook Change Account dialog box

Exchange Fast Access combines the instant-access of Online Mode with the offline capabilities and syncing robustness of Cached Exchange Mode, specifically in scenarios when syncing data locally would take enough time to be noticed by the user (for example, initial sync, resume, returning from vacation).

When you first start Outlook 2013, you immediately see your most recent email messages and a completely up-to-date calendar. Outlook 2013 caches items in the background to prepare for offline use without affecting the user experience. Sync Slider allows an Outlook 2013 user to limit the email messages that are locally synchronized in an Outlook data file (.ost). By default, if Cached Exchange Mode is enabled, Outlook 2013 caches email messages only from the last 12 months and removes anything older from the local cache. Users can view messages that were removed from the local cache by scrolling to the end of a message list in a folder and clicking the message Click here to view more on Microsoft Exchange. Users can also change how much email to keep offline. You, the administrator, can change the default age or enforce the age of email messages that are removed from the local cache.

You can lock the settings to customize Cached Exchange Mode using the Outlook Group Policy Administrative template. Or, you can configure default settings by using the Office Customization Tool (OCT). If you use the OCT, users will be able to change the settings later in the Outlook Change Account dialog box.

Before you begin

Before you start deployment, review Plan a Cached Exchange Mode deployment in Outlook 2013 and Office Customization Tool (OCT) reference for Office 2013 to determine which settings beyond the default ones you might need to configure for Cached Exchange Mode. You don’t need to customize Cached Exchange Mode if you don’t want to, though—the default settings are appropriate for most organizations.

If this is your first time using Group Policy template files or Office Customization Tool files, take some time to get familiar with them. Then, if you decide to configure Cached Exchange Mode through Group Policy, read the overview of Group Policy. If you decide to configure Cached Exchange Mode using the OCT, start with the OCT reference.

To download the Outlook 2013 administrative templates, see Office 2013 Administrative Template files (ADMX/ADML) and Office Customization Tool.

Configure Cached Exchange Mode

Use the following procedures to configure Cached Exchange Mode settings. Remember that customizing Cached Exchange Mode settings is optional.

To configure Cached Exchange Mode settings by using the OCT

  1. In the OCT tree view, find Outlook, and click Add Accounts. In the Account Name column, click the account you want to configure, and click Modify to display the Exchange Settings dialog box.

  2. Click More settings.

  3. Click the Cached Mode tab.

  4. Click Configure Cached Exchange Mode, and select the Use Cached Exchange Mode check box to enable Cached Exchange Mode for users. (By default, Cached Exchange Mode is disabled.)

  5. Choose a default download option on the Cached Mode tab:

    • Download only headers   Users see header information and the beginning of the message. They can download the full message in several ways—for example, by double-clicking to open the message or by clicking Download the rest of this message now in the reading pane.

    • Download headers followed by the full item   All headers are downloaded first, and then full items are downloaded. The download order might not be chronological, but that shouldn’t be noticeable to the user. Outlook downloads headers followed by full items in the folder that the user is currently accessing, and then it downloads headers followed by full items in folders that the user has recently viewed.

    • Download full items   Full items are downloaded. We recommend this option unless you have a slow network connection. The download order might not be chronological, but that shouldn’t be noticeable to the user. Outlook downloads full items in the folder that the user is currently accessing, and then it downloads full items in folders that the user has recently viewed. You might want to pair this with the On slow connections, download only headers option.

  6. (Optional) Disable download of shared mail folders (like a delegated inbox) and other folders (like a shared calendar) as part of Cached Exchange Mode synchronizations to users' .ost files by clearing the Download shared non-mail folders option. By default, in Outlook 2013, shared mail and non-mail folders are downloaded—which naturally increases the size of users' .ost files. It’s important to know that the setting Download shared non-mail folders applies to both mail and non-mail shared folders. If you want to only disable download of shared mail folders, do the following:

    1. In OCT, in the tree view, locate Additional Content, and click Add registry entries.

    2. In the reading pane, click Add.

    3. Enter the following:

      Registry key to disable download of shared mail folders

      Root Data type Key Value name Value data

      HKEY_Current_User

      REG_SZ

      Software\Microsoft\Office\15.0\Outlook\Cached Mode

      CacheOthersMail

      0

    4. Click OK.

  7. (Optional) Download users’ Public Folder Favorites to users' .ost files as part of Cached Exchange Mode synchronizations by choosing the Download Public Folder Favorites option. By default, Public Folder Favorites are not downloaded. Just like with shared folders, downloading Public Folder Favorites increases the size of users' .ost files. Also, synchronizing Public Folder Favorites might cause additional network traffic that could be annoying for users who have slow connections.

To configure Cached Exchange Mode settings using Group Policy

  1. In Group Policy, load the Outlook 2013 template.

  2. Open the Group Policy Management Console (GPMC), and in the tree view, expand Domains, and expand Group Policy Objects.

  3. Right-click the policy object that you want, and click Edit. The Group Policy Management Editor window opens.

  4. In the tree view, expand User Configuration, expand Administrative Templates, expand Microsoft Outlook 2013, expand Account Settings, and then click Exchange. You can also expand Exchange, and click Cached Exchange Mode.

  5. In the reading pane, in the Setting column, open the policy that you want to set by double-clicking it. For example, in the Exchange reading pane, open Use Cached Exchange Mode for new and existing Outlook profiles.

  6. Select Enabled, and select an option (if appropriate).

  7. Click OK.

To configure a default .ost location by using Group Policy

  1. In Group Policy, load the Outlook 2013 template.

  2. Open the Group Policy Management Console (GPMC), and in the tree view, expand Domains, and then expand Group Policy Objects.

  3. Right-click the policy object that you want, and click Edit. The Group Policy Management Editor window opens.

  4. In the tree view, expand User Configuration, expand Administrative Templates, expand Microsoft Outlook 2013, expand Miscellaneous, and then click PST Settings.

  5. Double-click Default location for OST files to open it.

  6. Click Enabled to enable the policy setting.

  7. In the Default location for OST files text box, enter the default location for .ost files. For example:

    %userprofile%\Local Settings\Application Data\Microsoft\newfolder.

  8. Click OK.

    You can define a new default location for both Personal Outlook data files (.pst) and .ost files. After you click PST Settings in the tree view, double-click to open the Default location for PST files setting in the reading pane.

To prevent a new .ost file from being created

  1. In Group Policy, load the Outlook 2013 template.

  2. Open the Group Policy Management Console (GPMC), and in the tree view, expand Domains, and expand Group Policy Objects.

  3. Right-click the policy object that you want, and click Edit. The Group Policy Management Editor window opens.

  4. In the tree view, expand User Configuration, expand Administrative Templates, expand Microsoft Outlook 2013, expand Account Settings, and then click Exchange.

  5. Double-click Do not create new OST file on upgrade to open it.

  6. Click Enabled to enable the policy setting, and then click OK.

See also

Plan a Cached Exchange Mode deployment in Outlook 2013
What's new in Outlook 2013