University of Oregon

Entourage Mailbox Size Reduction


This article explains how to reduce the size of mailboxes when using Microsoft Entourage.

Create an Email Archives folder on your computer

This is the location where your Archive files will live. We recommend creating this on your Desktop so that it is easy to locate.
  1. Minimize all applications so that you're looking at your desktop.
  2. Right-click on your desktop and select New Folder
  3. Name your folder "Email Archives" (no quotes).

Organizing your Archives

We recommend archiving mail based on date. For example, you could archive by year, and would have a 2007 Received.mbox, a 2008 Received.mbox, 2009 Received.mbox, and so on. (You may want to do Sent Items separately.) You may find it more useful to archive by topic, or other criteria that may be easier for you. If you have a lot of mail, you should try to split it up into several folders to reduce their individual sizes. Having a single, very large MBOX file may make it more prone to corruption.

Archiving Mail

  1. Go to File > New > Folder
  2. Name it something appropriate to the criteria you are archiving by. In this example, we'll use "2009 Received".
  3. Select the messages you wish to archive. For example, for 2009 messages, we sort by Date and select messages received in 2009.
  4. Go to Message > Move To > Choose folder
  5. Select the folder you created in Step 1.
  6. When the messages have been moved, click and drag the folder out to your Email Archives folder on your desktop.
  7. For very large numbers of messages, this may take several minutes. You will see the .MBOX file appear in your Email Archives folder when it is finished.
  8. You can now delete the folder you created in Entourage to free up space. 
  9. Right-click on Deleted Items and choose Empty Deleted Items.

Set up Backups

Now that you have your Archive files on your computer, you should ensure that your data is being backed up to an external hard drive. For tips on backing up, see Backing Up Your Data or contact your local IT support.

Finding Archived Mail

  1. In Entourage, scroll down in the left-hand pane (Folder List) to On My Computer. Expand it if it is collapsed by clicking the arrow next to it.
  2. In Finder, browse to your Desktop's Email Archives folder and select the MBOX file that contains the messages you need.
  3. Click & Drag the mbox file to the Inbox below On My Computer (it should highlight when your mouse is over it)
  4. When you release, Entourage may seem to freeze temporarily as it imports the data. Your mbox file should create a folder below Inbox containing the imported messages.

Note: changes made here will not affect the existing MBOX files.