The default (and only) sharing policy is: domain: * , action: Calendar sharing with free/busy information only. No mailboxes are added. Policy is not enabled (enabled: false) and default (default: true). How to achieve no sharing, not even free/busy.

Get-mailbox | ForEach-Object {Set-MailboxFolderPermission $_":\Calendar" -User default -AccessRights none} Now to set it routinely so that newly created mailboxes are set, run a scheduled powershell script task to run once a day.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Get-mailbox | ForEach-Object {Set-MailboxFolderPermission $_":\Calendar" -User default -AccessRights none} Now to set it routinely so that newly created mailboxes are set, run a scheduled powershell script task to run once a day.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Hi taniv Did you try above command, also you could Create a Sharing Policy, please refer to http://technet.microsoft.com/en-us/library/dd351201.aspx And below FAQ might also help: FAQ: Give Calendar Read Permission on all Mailboxes PFDavAdmin http://exchangeshare.wordpress.com/2008/05/27/faq-give-calendar-read-permission-on-all-mailboxes-pfdavadmin/ Cheers Zi Feng TechNet Community Support