How to Modify the One-Eighth Rule

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For Microsoft® Office Outlook® clients that use Offline Address Book version 2 and version 3a (OAB v2 and OAB v3a), the offline address book server initiates a full offline address book download if the size of the Changes.oab files are one-eighth or more in size of the full offline address book files. Use this procedure to modify the one-eighth rule.

Note

This setting does not apply to Outlook clients that use OAB v4. For clients that use OAB v4, the offline address book server generates a full offline address book download only if the size of the Changes.oab files are one-half or more in size compared to the full offline address book files.

Before You Begin

For information about how Microsoft Exchange Server 2003 calculates the overall number of directory changes, see "Overall Number of Directory Changes" in Using Offline Address Books.

Warning

Incorrectly editing the registry can cause serious problems that may require you to reinstall your operating system. Problems resulting from editing the registry incorrectly may not be able to be resolved. Before editing the registry, back up any valuable data.

Procedure

To modify the one-eighth rule

  1. On the Outlook client computer, open a registry editor, such as Regedit.exe or Regedt32.exe.

  2. Navigate to: HKLM\SOFTWARE\Microsoft\Exchange\Exchange Provider

  3. If the OAB Dif Divisor entry is not present in the right pane, create it. To do this, in the left pane, right-click the Exchange Provider subkey, point to New, and then click DWORD Value. Type OAB Dif Divisor, and then press ENTER.

  4. Double-click OAB Dif Divisor. In the Edit DWORD Value dialog box, type X (decimal) in the Value box, and then click OK. This setting example permits Outlook to download differential offline address book files that are up to one-Xth the size of the full offline address book. For example, if you enter 4 for the value, Outlook will download offline address books up to one-fourth the size of the offline address book.

    Note

    If the OAB Dif Divisor registry value is set to 0 (zero), Outlook will use 16 so that it does not divide by 0.

  5. Close the registry editor, and restart the Outlook client for the change to take effect.