Backing up PST files if something has changed

Question

Hi,

I am interested in learning more details about pst files as well.

I am interested in backing up pst files if something has changed. Unfortunately, Outlook modifies the pst even if Outlook is opened, nothing happens (no emails in or out etc) and Outlook is closed. Both the modified time changes and even the md5 changes! What the heck?! Who designed that?!

Worse, the file size of the pst doesn't necessarily change if a new email is received! This is amazing. It makes it impossible to tell if the pst is other than spuriously different from a previous version.

So, can you tell me if there is any way to tell if a pst file is different in content from a previous version of it?

Thanks!

Answer 1

How can you explain that just by opening and closing Outlook, and no emails were sent or received, that the size of the pst file can change by 7 MB?!

Answer 2

David,
Your original forum post was split. Let me review the original post and I will update with my reply here once that is completed.

Steve Smegner
Application Development Consulting Group

Answer 3

 

David,
The PST file has a database schema. Outlook mounts the PST and there are many possibilities for why this file could be changed. If the file was not closed properly a check and repair is done on the file. The PST contains not only email but tasks, contacts, rules, appointments, meetings, etc. Many of these items could have recurrences set and the calendar could be updated with new instances of the recurring item. The file could have archive rules set that could move and/or purge items. The file, once mounted, is accessible to desktop search and/or Office communicator. Indexes could be balanced or rebuilt. The PST typically preallocates empty space for efficiency. That could explain why the file does not change when a new item is received. It goes into a preallocated empty block. If space is too low it could pre-allocate more space and expand the file even though no new mail items have been retrieved.

So you can see that there are lots of things that could potentially change the file. And with those changes you will see times changed and MD5 changes.

But this is beyond the scope of this forum. This forum is for supporting the Open Specification documents. My suggestion is that you contact our developers support organization. An alternative is to review the MAPI and CDO APIs found online and through MSDN.

You may also want to try this forum for assistance: http://social.msdn.microsoft.com/Forums/en-US/vsto/threads/

Thanks.
Steve Smegner
Application Development Consulting Group

Answer 4

Backup and restore lost pst files make use of programmind method next one can help you http://www.outlook.fixtoolbox.com