The database will not automatically shrink, even if you move all of the mailboxes off of that database. What I recommend is to create your new databases (if you have the available disk space) and then move all of your mailboxes to the new databases. Once you have moved all mailboxes, you can delete the original database.Jim McBee - Blog - http://mostlyexchange.blogspot.com

Hello, I've 110 user mailbox store which is sizing of 800GB. I want to reduce the mailbox database size, I'm planning to create two database more and then re-arrange individual mailbox on that new DB. will this help me to reduce the mailbox database size and can i eliminate the old DB so that it will release the space to my HDD.

The database will not automatically shrink, even if you move all of the mailboxes off of that database. What I recommend is to create your new databases (if you have the available disk space) and then move all of your mailboxes to the new databases. Once you have moved all mailboxes, you can delete the original database.Jim McBee - Blog - http://mostlyexchange.blogspot.com

Hi Database wont be shrink even if your move mailbox from it to another database. If you want to shrink database , you have to do offline defragment. I think Jims advice is the best way. You can remove edb file and log file when you move mailbox to other database. TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Terence Yu TechNet Community Support

Hi Jim/Terence, I'll do as you suggested, and will update.