This works for Office365 or an internal Exchange server to disable the calendar on a Shared Mailbox or User’s Mailbox. First, you’ll have to pull up the Exchange Management Shell. Then run the following commands:

New-OwaMailboxPolicy –Name “New Policy Name”

Creates a new mailbox policy


Set-OwaMailboxPolicy –Identity “New Policy Name” –CalendarEnabled $false

Sets the calendar for all mailboxes under the policy to be off

Set-CASMailbox –Identity “shared mailbox” –OwaMailboxPolicy “newpolicy”

Applies the policy to the mailbox in question