Two Great Reasons to Compact Outlook Data Files

You're probably wondering, "What does it mean to compact Outlook data files, and why should I do it?" Let me explain.

Unless all your stuff lives on an Exchange server somewhere, your Outlook data is stored on your hard drive in one or more personal folders files, usually called .pst files The .pst refers to the file extension assigned to these kinds of files.

To recap, every Outlook data item (email message, task, contact, etc.) occupies space in a .pst file. So far so good.

Let's talk about what happens when you delete an Outlook item. First, the item appears in the Deleted Items folder, where it continues to take up space in the .pst file. If you've ever looked in Deleted Items, it is like a holding area for unwanted items. They're still available there and you can recover them if you wish.

When you empty the Deleted Items folder, anything in it is permanently gone. It can't be recovered. Emptying the Deleted Items folder removes the items in the folder, and also removes them from the .pst file. But things are not quite as they seem. While the item is no longer available in Deleted Items or the .pst file, the space it occupied in the .pst file remains tied up. Because of the way .pst files work, the space occupied by deleted items remains unavailable. So your .pst files just keep growing in size, no matter what you do.

Ever-growing .pst files cause two problems. First, they tie up an ever-growing chunk of your hard disk space. If you have lots of disk space available, that may not be an issue right now, but it will eventually become one, if for no other reason than that Outlook has limits on the size of .pst files it will work with.

The second problem is that the larger the .pst file is, the slower Outlook works. And that only makes sense. As Outlook has to sift through an ever-larger file to find the items it needs, it takes longer to get things done. That's why you need to compact Outlook data files every so often.

How Often Do I Need To Compact My Outlook Data Files?

How often you should compact files is an inexact science. If you feel that Outlook is running slowly, you should try compacting the files to see if it clears up the problem. Unless you are having problems, such as Outlook running very slow, or you really need to free up disk space, you should try to compact Outlook .pst files once or twice a year. It's not hard to do. It's a simple 4 step (for Outlook 2003) or 5 step (for Outlook 2007) process that anyone can do.

So how exactly do you compact Outlook data files? Your best bet is to follow the directions on this Why Compact Outlook Data Files? page. It provides the exact steps needed to compact the files for both Outlook 2003 and Outlook 2007. And once you finish doing that, I suggest you explore the rest of the site. It's full of information on making living with Outlook easier and more fun