Disable Offline Address Book Outlook 2007

Manually Change Offline Address Book Settings

You can manually edit your Registry and configure the following key to DISABLE the Offline Address Book (note that you will need to create the "Cached Mode" Registry key if it is not already present):
Outlook 2007

HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Cached Mode
Parameter: DownloadOAB
Type: REG_DWORD
Value: 0

Outlook 2003

HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Cached Mode
Parameter: DownloadOAB
Type: REG_DWORD
Value: 0

At this point, Outlook will no longer automatically download the offline address book. However, if you click the "Send/Receive" button within Outlook, by default it will reset your offline address book setting - in effect it re-enables the offline address book. To prevent this from happening, complete the following steps.
Open Outlook
Go to "Tools" > "Send/Receive" > "Send/Receive Settings" > "Define Send/Receive Groups"
Highlight the group "All Accounts" and click "Edit"
In Outlook 2007, check the "Include the selected account in this group" checkbox
Uncheck the "Download offline address book" checkbox
Click "OK"
Click "Close"