What is a good practice for users mailbox size and number of items in their mailbox. We have some users with mailbox sizes that I think are not big 1.2GB. But they may have a lot of items in their inbox. Is there a recommendation for mailbox stores? I have 10 mailbox stores and running in a CCR environment. Thanks

In previous versions of Exchange there were stricter recommendations, but honestly in Exchange 2007 most of them are gone. Mailbox size is far less of a concern than number of items, I generally say as a matter of practice keep your critical folder (inbox, contacts, calendar, sent, etc) item count around 2,500-5,000 items, ideally less than 1,000. The bigger concern is for the end user experience if they are using Outlook in cached mode, obviously it keeps an OST file local, so the larger the OST/mailbox size the more sluggish the performance on the end user. THanks, Jorge R. Diaz, PMP, CCNA, MCSA, MCSE, MCTS Senior Microsoft Consultant Planet Technologies, Inc. Check out My Blog!

This is what I was going to ask. Right now only a few users are running in cache mode. Is it recommended to run in cache mode?

I'd only run the users you have to in cached mode, ie. laptop users. People with desktops that never move and are always connected to the LAN don't really get any benefit from cached mode. Jorge R. Diaz, PMP, CCNA, MCSA, MCSE, MCTS Senior Microsoft Consultant Planet Technologies, Inc. Check out My Blog!

Hi, Cached Exchange Mode offers you the following benefits: After messages have been cached locally, typical user operations do not cause interactions that block the server. Quickflagging, marking a message as read, replying, and editing require a small amount of data to be pushed up to the server to keep the mailboxes synchronized. However, the pushing of data occurs in the background. This behavior causes much faster access to messages and to attachments, because you work from the local copy instead of the server copy. Additionally, Cached Exchange Mode causes no loss of conventional functionality. New e-mail notifications, full Global Address List details, free/busy lookup, public folder access, and delegate support function as expected. However, this is true only when a network connection to an Exchange Server computer is present. Cached Exchange Mode provides intelligent use of bandwidth. This functionality is enabled by synchronizing only headers on slow connections (connections that are slower than 128 kilobits per second [Kbps]). This functionality works only when a network connection is present. Additionally, Cached Exchange Mode offers administrators the following benefits: Reduced server load. After messages are cached locally, re-opening the same message does not require server transactions. Reduced network load. After messages have been pulled over the network one time, subsequent access to those messages does not cause additional network traffic. Because messages are also compressed, there is an additional reduction on network load. Gen Lin TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Thanks Gen Lin-MSFT