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The PST or Personal STorage file for Microsoft Outlook can easily grow to an extreme size. There are some tips for managing its size.
What can I do about Outlook's huge PST?
.pst files are one of Outlook's repositories for email, contacts, calendar information, and much more. (Not Outlook Express, by the way.) There's a physical limit on .pst size that's up around 2 gigabytes but more practical considerations like speed often make us want to control the size well before reaching that stage.
Step one is pretty obvious: delete what you can. Remember though, when you delete an item in Outlook it is simply moved to the Deleted Items folder which doesn't actually free the space until you empty it. So right click on the Deleted Items folder and select the Empty "Deleted Items" Folder to permanently delete its contents. This will free up the space that the deleted items took. But it will not immediately make the file smaller.
Click the video above for a one minute video showing you how to add a .pst to Microsoft Outlook. (Windows Media 9 format, 408,492 bytes.)
I'd Like Your Comments: let me know if you find the video above useful, or if you have suggestions to make this technique more helpful. Thanks!
Step two: after you've permanently deleted what you can, it's time to compress. Microsoft has a knowledge base article about compressing your .pst here. In short: File-> Data File Management, select your Personal Folders, Settings, and then Compact Now.
If the resulting file is still too big then it might be time to create an additional .pst. Outlook supports having multiple .pst's open at the same time. Your existing "Personal Folders" will remain the destination for email but you can easily move items into another .pst file.
To create a new .pst, select File-> New-> Outlook Data File..., then select "Office Outlook Personal Folders File (.pst)", and OK. In the next dialog box specify the location and name of your new .pst. I tend to place my archive .pst files in a common mail directory on another machine on my network but keeping it along side your existing personal folders is also common. Pick something that reflects how you'll organize your email and press OK. In the next dialog, specify the display name (I usually just use the file's name). Leave the other settings as they are for now and press OK.
Once you've created your new .pst, it will show up at the bottom of your email or file folders list. You can expand it, create sub folders in it, and drag and drop messages from your old .pst into your new one.
Your new .pst will automatically show up each time you open Outlook. You can explicitly close it if you like (Right click on it, and select "Close") which will speed up Outlook's start time somewhat. To open it again later, select File-> Open-> Outlook Data File....
Update 16-Jan-2004: In Outlook 2000 and in other versions of Outlook as well, it might be easier to find the "Compact Now" button this way: