tool to compact or defrag outlook personal file

as we use outlook in our corp. the .pst is more and more large.
i use the built-in compact feature of outlook2007, but it dose not shrink the large file well.
is there any method or 3rd party tool to compact or defrag the .pst file?

 

The only way the .pst file gets truly reduced or compacted is when emails are deleted and purged from the file. If you never delete anything, the file will continue to grow and you won't be able to compact it any. Compacting just removes deleted messages and thereby reduces the file size.

If you want to defrag it, there are many defragmenters available that will do that job.

 

thx for your reply,Kerodo
btw. dose it mean i have to del mails with large attachments before compacting the .pst file?

 

Anything you delete will help reduce the size of the file after you compact it. Deleting emails with attachments will help even more yes.