Outlook 2007 free/busy works slow or could not be retrieved
During migration from Exchange 2003 to 2007 we had the problem with Outlook 2007 client free busy response was slow , about 10 seconds to load .
To fix it .
Open registry editor on your Desktop(where outlook is installed)
Navigate to the following path : HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Options\Calendar
Create new DWORD value named UseLegacyFB and set value to 1
Note:
0 or not set will use default outlook settings
1 will use Public Folder based Free/Busy information
Read KB958934 to get more information.