You’re probably wondering, “What does it mean to compact Outlook data files, and why should I do it?” Let me tell you the story…
Every Outlook message, contact, note, and appointment, in short every item you see in Outlook, is either stored on a Microsoft Exchange server someplace (like your corporate data center) or on the hard drive in your computer. If your Outlook data is on your hard drive, it is stored in personal folder files. These files are generally referred to as .pst files, because .pst is the file extension for these kinds of files on your hard drive. Not surprisingly, every item in a .pst file takes up a bit of space on your hard drive.
So what happens to the .pst file when you delete something? The item goes to Outlook’s Deleted Items folder. Since the item can be recovered from there, it makes sense that the item still takes up some space in the .pst file.
Now what happens when you empty the Deleted Items folder? From our point of view, the item is completely gone. It can’t be recovered using any normal means. And the item is deleted from the .pst file too. But the amount of space occupied by the .pst file doesn’t shrink. This means that, unless you do something about it, your .pst files will just keep on growing in size.
This is why you have to compact your Outlook data files once in a while. As the .pst file gets bigger, it takes Outlook longer to do virtually everything. And the larger the .pst file gets, the smaller the amount of free space on your hard drive becomes. Compacting Outlook data files frees up the space that is unavailable because it used to hold an item that was deleted. Doing this will reduce the amount of space taken up by .pst files, and let Outlook function more efficiently.
How Often Should I Compact .pst Files?
How often you should compact files is an inexact science. If you are having problems with Outlook running slowly, you should compact the .pst files helps speed things up. 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. Compacting the files isn’t hard to do, although the process does differ slightly depending on whether you are using Outlook 2003 or Outlook 2007. Just follow 4 or 5 steps and you’re done.