Microsoft KB Archive/189310

= XCLN: Outlook 8.5 Speed Enhancements for Calendar Folder Access =

Article ID: 189310

Article Last Modified on 11/3/2004

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APPLIES TO


 * Microsoft Outlook 98 Standard Edition

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This article was previously published under Q189310



SUMMARY
When you use Outlook version 8.00, 8.01, 8.02, or 8.03 to open your Calendar folder, Outlook can be slow at startup. This behavior is caused by the manner in which those versions of Outlook display the Calendar form and data that is contained in the folder. The entire contents of the Calendar are retrieved before the Calendar information is displayed.

The background synchronization feature of Outlook 8.5 improves performance for users who work primarily connected to Microsoft Exchange Server. Outlook 8.5 automatically configures the Calendar to work from a local synchronized folder, and synchronizes the local folder with Microsoft Exchange Server periodically (see the "More Information" section for details). This enhancement improves performance for Outlook 8.5 users by making access to their Calendar local, and it decreases the load on Microsoft Exchange Server so that Exchange Server performance and scalability also improve.



Outlook 8.00, 8.01, 8.02, and 8.03 (Outlook 97)
In these versions of Outlook, the first time the Calendar is selected after the client startup, the entire contents of the Calendar are retrieved before the Calendar information is displayed to the user. After this information has been retrieved from the server, it is cached locally so that changing views to another folder and back to Calendar allows the data to be displayed quickly. Changes to the Calendar that are made by the owner or users with access to the Calendar are displayed as the cache is updated. This has a slightly slow response time if you change the view to Inbox, change the Calendar, and then change the view back to Calendar. This behavior occurs because the Calendar local cache being reloaded. If you are using an offline folder (.ost file), the contents of the folders are not fully synchronized until you manually select that option from the Tools menu or when you quit Outlook.

Outlook 8.5 (Outlook 98)
To allow faster access to Calendar information, Outlook 8.5 uses a different method for users who work primarily connected to Microsoft Exchange Server. Upon startup or selection of the Calendar folder, the Calendar information is displayed very quickly. To achieve this, the Outlook 8.5 client works in a mode called "Primarily Offline." Working primarily offline allows the user the speed benefit of working offline from a local copy of the Calendar information, while being synchronized with the current information on the Exchange Server mailbox store. Outlook 8.5 manages this by running Calendar folder synchronization in a background thread that is transparent to the user. The background synchronization process synchronizes the Calendar information to a local offline folder (.ost file).

Offline Folder (.OST file)
If an Outlook 8.5 client profile is already configured for offline use, the Primarily Offline Calendar feature uses the existing .ost file to access and synchronize Calendar information. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

161889 XCLN: OST and PST Quick Reference

If the Outlook 8.5 client profile is not configured for offline use, an .ost file is created specifically for the Primarily Offline Calendar feature. This .ost file is created in the \Application Data\Microsoft\Outlook folder on the user's computer for Microsoft Windows 95 applications, and in the  \Profiles\User\Application Data\Microsoft\Outlook folder for Microsoft Windows NT installations.

Calendar Updates
When a user who is working in Primarily Offline mode makes a change to his or her Calendar (local .ost file), a background synchronization thread is initiated after 10 seconds, making the local and server-based Calendars identical. If a change is made to the user's server-based Calendar (by a delegate or another user with proper permissions), Outlook 8.5 is notified by the Exchange Server computer, and a background thread is initiated to synchronize the local Calendar with the server Calendar.

NOTE: This feature works with all versions of Exchange Server.

Additional query words: 97 8.5

Keywords: kbinfo KB189310

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