Outlook performance (seriously) degrades as your mailbox grows in size. For most users, the task of managing e-mails can seem difficult, but when you know the key areas upon which to focus, keeping your mailbox size down is easy. Here are some tips to help.

1. Delete attachments immediately after you send them

Delete attachments from mail that you send immediately after you hit send; after all, the attachment is already a file on your computer or the server somewhere anyhow.  To do that, open the sent e-mail, right click on the attachment, and choose remove.  When you close the e-mail again, it will ask if you want to save.   This preserves the e-mail transaction itself so you know what you said and when you sent it, but without the space-gobbling attachment.

Use this tip so you won't forget where the attachments were in the first place:

When you send attachments, use Windows Explorer to browse for the file(s) you want to send, then right click on them and choose "send to" then "mail recipient".  That will list all the attachments in the body of the e-mail, making it easy to see what was sent when you delete the attachment after sending. You can easily edit the text that defaults into the subject line.

2. Save attachments received from others on your server/computer, then delete them from the email.

For received attachments, if they're important, use the "save attachments" feature from the file menu (or by right-clicking on the attachement) and save them to an appropriate location on your local computer or server.  Use the same procedure as above to delete the attachment(s) from the e-mail.

3. How to find larger e-mails

You can group mail by size by clicking on the "size" column, this will sort your e-mails from largest to smallest.  Then you can see which e-mails are your biggest offenders. A lot of the time, you'll find stuff in there you didn't even know you had, much less care to keep.

To see how big all your folders are and where the problem lies, choose the "folder view" by clicking on Folder List in the icons underneath the folder tree (underneath mail, calendars, contacts, tasks, etc.) in the left pane. The "Folder List" button is outlined in red below:

Then scroll down the folder tree and at the bottom, you'll see "folder sizes" (outlined in red below); click on that & it will tell you how large your total mailbox is and how much room each specific folder is occupying.

Important Notes About Large Mailboxes:
Most users have no idea how large their mailboxes have become. Cleaning up a large mailbox can be a MAMMOTH task, but it is very important. When the overall size of the mailbox exceeds 2 GB, not only will the user be experiencing horrible performance when trying to view and manage mail, but there is a very high risk of data corruption! While there are utilities which can attempt to repair corrupt mailboxes, they don't always work. The problem is exacerbated if someone gets a new computer and tries to transfer their mail from the old PC. While it may have limped along before, you can encounter serious problems recovernig mail when you come to import mail to your new system from your oversized former mailbox. Most people will not have the expertise to know how to do this which translates into added co$t!! Mail recovery can be very time consuming too, so that's more $$$...

If your mail is part of an Exchange server, if your administrator has not put mailbox size limits in place, your mailbox will affect the overall size & performance of the Exchange database. Ca-ching: even more cost to fix!

So finally, after you've cleaned up old mail, mail with attachments etc, that which is left, if you REALLY have to keep it, you can use the Archive feature to further reduce the mailbox size.  Be careful though:  I recommend changing the path/location of the archive file to somewhere on the server, preferably your personal drive, or if you aren't attached to a server, at least to a folder somewhere in your "my documents" (which, of course, you back up - right!?).  Otherwise, if something happens to your PC, then the archive may be lost. The default folder is C:\Documents and Settings\<username>\Local Settings\Application Data\Microsoft\Outlook. Aargh, right? Yup, I always wonder which genius came up with such a pathway to bury stuff. Oh, and it's different and even harder to find in Vista...

We reccomend simply keeping your mailbox size to a "minimum" and not relying an archive folder, which only transfers the problem to another file that, when it gets too big, can corrupt and all that anyway. How much is a "minimum"? I guess that's pretty subjective, but you really start to see performance issues when a mailbox gets over about 500 MB. Over 1 GB, it starts to crawl, and, well, after that... You have to ask yourself, how important is it to keep a lot of that "correspondence" anyway?