Determining Mailbox Size for All Exchange Users

To determine the size of users' mailboxes on a Microsoft Exchange server, the following steps can be taken [Note: this procedure was written for Exchange 6.5 running on a Windows Small Business Server (SBS) 2003 system]
  1. Click on Start
  2. Select All Programs.
  3. Select Microsoft Exchange.
  4. Select System Manager.

    Exchange System Manager

  5. Click on "+" to left of Servers to show the available servers.

    Exchange System Manager Available Servers

  6. Click on "+" to left of the appropriate server to show the entries beneath it.

    Exchange System Manager Server Entries

  7. Click on "+" to left of First Storage Group to show the entries beneath it.

    Exchange System Manager Storage Group Entries

  8. Click on "+" to left of Mailbox Store to show the entries beneath it.

    Exchange System Manager Mailbox Store Entries

  9. Click on the Mailboxes entry to see the list of mailboxes.

    Exchange Mailboxes

You can click on the Size (KB) column header to sort the entries by size. Clicking on it a second time will reverse the sort order.

References:

  1. Mailbox Limits
    Outlook Exchange
  2. Outlook Exchange Mailbox size limit
    Date: May 23, 2008
    Computing.Net
  3. Exchange mailbox size log/email admin notification
    By: James Eidson
    Date: February 7, 2008
    James Eidson - Computer Blog