Microsoft KB Archive/259077

= XCLN: Information About .ost File Synchronization Sizes =

Article ID: 259077

Article Last Modified on 2/21/2007

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APPLIES TO


 * Microsoft Outlook 97 Standard Edition
 * Microsoft Outlook 98 Standard Edition
 * Microsoft Outlook 2000 Standard Edition
 * Microsoft Exchange Server 5.5 Standard Edition

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This article was previously published under Q259077



IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry



SYMPTOMS
When you use an Offline Folder (.ost) file and you synchronize an e-mail message that has an attachment, the amount of data that is transmitted to the server may exceed the original size of the e-mail message.



CAUSE
The following example demonstrates how the size of a message may increase.

If you receive an e-mail message that is 1 megabyte (MB) in size, and then follow this procedure, the size of the message increases:
 * Synchronize your .ost file.
 * Start Outlook in offline mode.
 * Forward the message that you received to someone else.
 * Synchronize your .ost file with your mailbox while you work offline.

During this last synchronization, you may see much larger data sizes for the following reasons:
 * One copy of the message is transferred to the server from your .ost file to send the message to the recipients (the first MB).
 * The copy of the message in your .ost file's Sent Items folder is synchronized with the server's Sent Items folder (the second MB).
 * Because you forwarded the message, the copy of the message in your .ost file's Inbox folder changes to have a You forwarded this message on flag. This change must be synchronized with your server-based Inbox folder. Because you cannot synchronize at the field level, the entire message must be transmitted (the third MB).
 * If you carbon copy (Cc) yourself when you send a message, your .ost file copies the new message (the forth MB).



WORKAROUND
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Although you cannot change the method that Outlook uses to synchronize with the server, you can reduce the size of the data that is stored on your computer.  When you use an .ost folder filter, you can specify conditions about the data that individual folders receive, including the size. Typically, you do this to either your Sent Items folder or your Inbox folder. However, when you enable this option, you do not have access to these files when you work offline. To specify conditions for an individual folder:  In the Folder List pane, right-click the folder that you want to prevent from synchronizing with larger files, and then click Properties.

If you do not see the Folder List pane, click Folder List on the View menu. On the Synchronization tab, click Filter. Click the More Choices tab, and then choose the size and the conditions that you want the folder to receive.  When you enable the RFNoTrack registry value, Outlook cannot synchronize entire copies of a message if you change either the You replied to this message on or the You forwarded this message on flags. To enable RFNoTrack:  Click Start, click Run, type regedit, and then click OK.</li> Locate and click the following registry key:

In Outlook 97 and Outlook 98: 

HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Outlook\Options\Mail

In Outlook 2000:

HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Outlook\Options\Mail

</li> On the Edit menu, click Add Value, and then add the following registry value:

Value Name: RFNoTrack

Data Type: REG_DWORD

Value: Decimal 1

</li> Quit Registry Editor.</li></ol> </li> Try not to carbon copy (Cc) yourself when you send messages. If you do not Cc yourself when you send messages, fewer messages are in your Inbox when it is synchronized. When you click Reply All to reply to a message, you may not be able to avoid getting the message. Use an .ost filter on your Inbox to avoid this:  Right-click your Inbox folder in the Folder List pane, and then click Properties.

If you do not see the Folder List pane, click Folder List on the View menu.</li> On the Synchronization tab, click Filter.</li> Click the More Choices tab, and then choose the conditions that you want the folder to receive.</li></ol> </li></ul>

<div class="status_section">

STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

Keywords: kbbug kbnofix KB259077

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