You might want to change from using availability service to classic public folder usage for accessing and storing free/busy information.
What you have to consider if using free/busy information with public folders in a pure Exchange 2010 environment after installing Exchange without a public folder store?
After installing Exchange 2010 by default your Exchange 2010 does not have any public folder store!
So all clients must be Outlook 2007 or Outlook 2010 to use availability service whcih collects free/busy information directly from mailbox stores.
There are several reasons for modifiying this configuartion i.e. if you want to use clients like Outlook 2003 or if you want to share free/busy information between different Exchange organizations with GALsync.
Follow these recommendations to have a new public folder store with storing free/busy in system public folders.
Create a new public folder store: But having a public folder store you do not have automatically free/busy times available. If you check presense of the required system folder with MDBVU.exe you will discover: no folder present. Follow for this our blog article How to check free/busy information in Exchange.
How to create this folder: f you use Outlook 2003 create a new appointment and save it. The best for having this information immediatly working start Outlook again from console with parameter /cleanfreebusy. This will save the new appoinment directly without time lag into the system folder.
Because Outlook 2007 and higher contacts Availability web service for free/busy lookups – and Availability service looks directly into users calendar, by default it is not possible to get free/busy information from public folders. So, in an Exchange 2007 environment you have to force Outlook 2007 clients not to use Availability service. This you can do by:
- add a dword “UseLegacyFB” with value 1
Note: Outlook 2010 does not use this key, even if it is configured ( see also blog GALsync, Free/Busy, Exchange 2010, Outlook 2010 and Public Folders ).
If you check presense of the required system folder with MDBVU.exe you will discover now the a public folder with a NON_IPM_subtree folder called Schedule++ Free/Busy (Follow for this our blog article How to check free/busy information in Exchange.).
For each user there is a special *.eml-file containing his free/busy data.
Paul Robichaux Blog: Creating a public folder store for Exchange 2007 free/busy or
Technet Articel At Least One Exchange 2007 Public Folder Store is Required
GALsync Special – Part 2 :: Free Busy