Hi All, I have an ExchangE 2007. In order tu use export-pst i installed exchange 2007 EMC and EMS on a XP computer. All the mailboxes have a storage limit of 50MB. However, after running export-pst the size of some pst are bteween 300-500 MB. What could it be wrong? Regards. Jos Osorio.

Exchange server stores data more efficiently than PSTs do. Mike Crowley | MVP My Blog -- Planet Technologies

Hi Mike, So, there is no issue, right? Regards. Jos Osorio.

PSTs are a rather inefficient way to store data. Many attributes are stored twice. But this alone could not explain such a difference. Are you really sure that some mailboxes not larger than 50 MB have a corresponding PST file worth 300-500 MB? You can set storage limits on the Mailbox Database and on individual Mailboxes. Perhaps the values set on some of your mailboxes allow for 300-500 MB. Configuring Message and Mailbox Limits in Exchange 2007 http://www.exchangeinbox.com/article.aspx?i=140MCTS: Messaging | MCSE: S+M

Hi John, I've already checked Mailbox Database and on individual Mailboxes Limits. These users inherit the Mailbox Databse Limit which is 50MB.Regards. Jos Osorio.

Well, not too long ago I exported several hundred .PST files (100 MB - 10 GB), and I did see a considerable increase in the .PST files as compared to the mailboxes, but not that kind of increase you are talking about. However, my experience with exporting to .PST does not allow for any general statements. And in my first answer, I forgot about at least two things: (1) The April 2007 Outlook 2007 update introduced a new data structure for .pst files and for .ost files. That should account for an increased size of about 20 %. Microsoft says: If you have a large Exchange mailbox, you will have an .ost file that is even larger. For example, if the mailbox size is 350 megabytes (MB), the .ost file size can be 475 MB or larger. (2) In addition, Exchange 2007 will export dumpster items. So perhaps there is no issue at all. Anyhow, I would (if granted permissions) have opened one or two of these over-sized .PST files and made some spot checks. You may experience performance problems when you are working with items in a large .pst file or in a large .ost file in Outlook 2007 http://support.microsoft.com/kb/932086 Large is not *always* best when it comes to performance (but it helps) – Mailbox Performance in Exchange and Outlook 2010 http://sysadmin-talk.org/2010/05/large-is-not-always-best-when-it-comes-to-performance-but-it-helps-mailbox-performance-in-exchange-and-outlook-2010/ MCTS: Messaging | MCSE: S+M

Thanks Jon.Regards. Jos Osorio.