When this registry data exists, Outlook uses free/busy information from an Exchange public folder instead of using the Exchange Availability Service. The Suggestions Pane and the Add Rooms features both require the Availability Service.
To resolve this problem, make the following change to the UseLegacyFB value.
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
On the File menu, click Exit to exit the Registry Editor.
fixit fix it fixme