I've been searching on the Internet but never found an answer for this...The question applies to an Exchange 2007/Outlook 2007 environment. Will break it down into points so it's easier to answer :) 1. Ok, so Domain\User1 has a maillbox and accesses from Outlook using cached mode. The 'cache' part is kept in the OST file of the user, correct? 2. If User1 accesses a shared mailbox (e.g. Domain\Marketing), is this now cached within the same OST file too? Or is a seperate OST file created? Or is Marketing accessed as if it were in 'online with Exchange mode'? 3. Now, within the Exchange Management Console, there is a section that shows what Mailbox features are enabled for a user (OWA, Activesync, MAPI etc) for User1. Is this for ALL mailboxes that this user accesses, or just the mailbox for the account that we are viewing the properties for? 4. If I was to go to the Properties for Marketing and disable MAPI, will this prevent all users from accessing Marketing via MAPI?

Settings for a mailbox apply to just that mailbox, not the user who is accessing them. Therefore if you disable MAPI for a shared mailbox then no one will be able to access that mailbox using Outlook. With Outlook 2007 additional mailboxes are not cached by default, they are live only. This behaviour changes with Outlook 2010 if you use the Additional Account method. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.