if you're removing the email from the mailbox or using shortcutting then yes, archiving naturally will decrease the mailbox size which, in turn, should result in a smaller OST file.

when you say you rebuilt OST without EV, what does that mean?

what version of Outlook on the client, Exchange, and EV server and client are you using?

My concern is regarding the OST being 19 GB and corrupt. Is it possible that a corrupt OST could cause it to not be able to reclaim unused space?  Perhaps running a repair on the OST could have also fixed it?

As Andrew referenced, depending on your shortcut creation rules, EV will normally decrease the total size of the Mailbox.  However, some factors to take into consideration:

- Entire message content.  Setting shortcut creation to this means that the only space reclaimed will be from the removal of attachments.

- Small items.  In some cases, where an item is very small, less than 4 KB, the shortcut may actually be slightly larger due to the additional mapi properties and EV specific content.

As a general rule I try to keep any PST or OST under 14 GB for stability reasons.

Hope this helps.

I believe you are right JW2, the following article describes compacting the OST, which appears to be a manual process:

http://www.ostfile.com/compact-ost-file.html

Hope this helps.

I recently came across this registry key and wondered if it might be having an impact.  We found very recently it causes big delays opening items in VV if it's set but it might at least be interesting to set it to see if it impacts the size of the OST?

http://support.microsoft.com/kb/2022995

the comments about the OST file not reducing in size on its own is not completely accurate. Outlook has a built-in mechanism to do just that but it's not going to work of the OST file is corrupt or if Outlook is closed most of the time.

john, have you sorted this out yet?