Novax,

To add to the above posts, when you Export your entire mailbox, contacts and calendar information, you run the risk of corrupting the .PST if the data exceeds the Microsoft standard of 2gigs.

Best practices is perform the export of all Email data only, then a separate export of your calendar items to a .CSV and Contacts to another .CSV.

Also note, When performing an export, you will only have the items found in the mailbox on that day. Anything after that will not be stored in the .PST or .CSV.

Since you mentioned your Exchange server being In house, check to see if they have a back up restoration enabled. this is out of my scope but perhaps this link can help.

http://msdn.microsoft.com/en-us/library/dd877010.aspx

Best Regards,