The attachment problem in Outlook is so notorious that a third party has stepped in with a solution that helps you cut down the size of your .pst files by removing attachments. The free Kopf Outlook Attachment Remover] saves attachments from Outlook, stores them on your local disk and replaces the attachments with a link to the stored file. You'll be able to open the attachment as you would normally, except that Outlook will grab the file from disk, rather than from inside its .pst file.
You can have the program automatically go through entire directories, removing attachments and replacing them with links, or you can instead do it e-mail by e-mail. Note that in Outlook, it will look as if the file is still there -- you'll see the file icon as you normally do for an attachment. But the file is actually on disk, not in Outlook.
Outlook 2007 includes another tool for shrinking the size of your .pst file by targeting your fattest folders. Select Tools -- Mailbox Cleanup and click the View Mailbox Size button. You'll see a screen like the one shown below.
There will be a list of folders, along with the total size of each folder. That will tell you where you'll be able to get the most reduction by cleaning out e-mails -- and their bloat-inducing attachments. After you find the largest folders, go back to the Outlook main screen and tackle those first, searching for unnecessary e-mails and attachments and deleting them.
After you've used all of these techniques for deleting attachments and e-mails, it's time to compact your .pst file. Normally, when you delete files and attachments, there are essentially blank spaces left in your .pst file that take up bytes.
Compacting the file eliminates those blank spaces and shrinks the total size of the file. To do so, select File -- Data File Management and double-click the Personal Folders entry. Then click Compact Now.
Annoyance No. 3
Why can't I find where my $#%^(@"* Outlook data is stored? All of your mail, contacts, attachments, calendar information and so on -- pretty much the whole Outlook data shebang -- is stored in a single .pst file. You often need to know where that file is located if you want to, for example, back it up or move it between machines. But Microsoft has a penchant for changing the .pst location from version to version of Outlook, and you might have a hard time finding it.
In addition to the .pst data file, Outlook uses a variety of other files that do things such as store your personal preferences. You often want to know their locations as well.